java.net
Class URLConnection

java.lang.Object sample code for java.lang.Object definition code for java.lang.Object 
  extended by java.net.URLConnection
Direct Known Subclasses:
HttpURLConnection sample code for java.net.HttpURLConnection definition code for java.net.HttpURLConnection , JarURLConnection sample code for java.net.JarURLConnection definition code for java.net.JarURLConnection

public abstract class URLConnection
extends Object sample code for java.lang.Object definition code for java.lang.Object

The abstract class URLConnection is the superclass of all classes that represent a communications link between the application and a URL. Instances of this class can be used both to read from and to write to the resource referenced by the URL. In general, creating a connection to a URL is a multistep process:

openConnection() connect()
Manipulate parameters that affect the connection to the remote resource. Interact with the resource; query header fields and contents.
---------------------------->
time
  1. The connection object is created by invoking the openConnection method on a URL.
  2. The setup parameters and general request properties are manipulated.
  3. The actual connection to the remote object is made, using the connect method.
  4. The remote object becomes available. The header fields and the contents of the remote object can be accessed.

The setup parameters are modified using the following methods:

and the general request properties are modified using the method:

Default values for the AllowUserInteraction and UseCaches parameters can be set using the methods setDefaultAllowUserInteraction and setDefaultUseCaches.

Each of the above set methods has a corresponding get method to retrieve the value of the parameter or general request property. The specific parameters and general request properties that are applicable are protocol specific.

The following methods are used to access the header fields and the contents after the connection is made to the remote object:

Certain header fields are accessed frequently. The methods:

provide convenient access to these fields. The getContentType method is used by the getContent method to determine the type of the remote object; subclasses may find it convenient to override the getContentType method.

In the common case, all of the pre-connection parameters and general request properties can be ignored: the pre-connection parameters and request properties default to sensible values. For most clients of this interface, there are only two interesting methods: getInputStream and getContent, which are mirrored in the URL class by convenience methods.

More information on the request properties and header fields of an http connection can be found at:

 http://www.ietf.org/rfc/rfc2068.txt
 
Note about fileNameMap: In versions prior to JDK 1.1.6, field fileNameMap of URLConnection was public. In JDK 1.1.6 and later, fileNameMap is private; accessor and mutator methods getFileNameMap sample code for java.net.URLConnection.getFileNameMap() definition code for java.net.URLConnection.getFileNameMap() and setFileNameMap sample code for java.net.URLConnection.setFileNameMap(java.net.FileNameMap) definition code for java.net.URLConnection.setFileNameMap(java.net.FileNameMap) are added to access it. This change is also described on the Compatibility page. Invoking the close() methods on the InputStream or OutputStream of an URLConnection after a request may free network resources associated with this instance, unless particular protocol specifications specify different behaviours for it.

Since:
JDK1.0
See Also:
URL.openConnection() sample code for java.net.URL.openConnection() definition code for java.net.URL.openConnection() , connect() sample code for java.net.URLConnection.connect() definition code for java.net.URLConnection.connect() , getContent() sample code for java.net.URLConnection.getContent() definition code for java.net.URLConnection.getContent() , getContentEncoding() sample code for java.net.URLConnection.getContentEncoding() definition code for java.net.URLConnection.getContentEncoding() , getContentLength() sample code for java.net.URLConnection.getContentLength() definition code for java.net.URLConnection.getContentLength() , getContentType() sample code for java.net.URLConnection.getContentType() definition code for java.net.URLConnection.getContentType() , getDate() sample code for java.net.URLConnection.getDate() definition code for java.net.URLConnection.getDate() , getExpiration() sample code for java.net.URLConnection.getExpiration() definition code for java.net.URLConnection.getExpiration() , getHeaderField(int) sample code for java.net.URLConnection.getHeaderField(int) definition code for java.net.URLConnection.getHeaderField(int) , getHeaderField(java.lang.String) sample code for java.net.URLConnection.getHeaderField(java.lang.String) definition code for java.net.URLConnection.getHeaderField(java.lang.String) , getInputStream() sample code for java.net.URLConnection.getInputStream() definition code for java.net.URLConnection.getInputStream() , getLastModified() sample code for java.net.URLConnection.getLastModified() definition code for java.net.URLConnection.getLastModified() , getOutputStream() sample code for java.net.URLConnection.getOutputStream() definition code for java.net.URLConnection.getOutputStream() , setAllowUserInteraction(boolean) sample code for java.net.URLConnection.setAllowUserInteraction(boolean) definition code for java.net.URLConnection.setAllowUserInteraction(boolean) , setDefaultUseCaches(boolean) sample code for java.net.URLConnection.setDefaultUseCaches(boolean) definition code for java.net.URLConnection.setDefaultUseCaches(boolean) , setDoInput(boolean) sample code for java.net.URLConnection.setDoInput(boolean) definition code for java.net.URLConnection.setDoInput(boolean) , setDoOutput(boolean) sample code for java.net.URLConnection.setDoOutput(boolean) definition code for java.net.URLConnection.setDoOutput(boolean) , setIfModifiedSince(long) sample code for java.net.URLConnection.setIfModifiedSince(long) definition code for java.net.URLConnection.setIfModifiedSince(long) , setRequestProperty(java.lang.String, java.lang.String) sample code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String) , setUseCaches(boolean) sample code for java.net.URLConnection.setUseCaches(boolean) definition code for java.net.URLConnection.setUseCaches(boolean)

Field Summary
protected  boolean allowUserInteraction sample code for java.net.URLConnection.allowUserInteraction definition code for java.net.URLConnection.allowUserInteraction
          If true, this URL is being examined in a context in which it makes sense to allow user interactions such as popping up an authentication dialog.
protected  boolean connected sample code for java.net.URLConnection.connected definition code for java.net.URLConnection.connected
          If false, this connection object has not created a communications link to the specified URL.
protected  boolean doInput sample code for java.net.URLConnection.doInput definition code for java.net.URLConnection.doInput
          This variable is set by the setDoInput method.
protected  boolean doOutput sample code for java.net.URLConnection.doOutput definition code for java.net.URLConnection.doOutput
          This variable is set by the setDoOutput method.
protected  long ifModifiedSince sample code for java.net.URLConnection.ifModifiedSince definition code for java.net.URLConnection.ifModifiedSince
          Some protocols support skipping the fetching of the object unless the object has been modified more recently than a certain time.
protected  URL sample code for java.net.URL definition code for java.net.URL url sample code for java.net.URLConnection.url definition code for java.net.URLConnection.url
          The URL represents the remote object on the World Wide Web to which this connection is opened.
protected  boolean useCaches sample code for java.net.URLConnection.useCaches definition code for java.net.URLConnection.useCaches
          If true, the protocol is allowed to use caching whenever it can.
 
Constructor Summary
protected URLConnection sample code for java.net.URLConnection.URLConnection(java.net.URL) definition code for java.net.URLConnection.URLConnection(java.net.URL) (URL sample code for java.net.URL definition code for java.net.URL  url)
          Constructs a URL connection to the specified URL.
 
Method Summary
 void addRequestProperty sample code for java.net.URLConnection.addRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.addRequestProperty(java.lang.String, java.lang.String) (String sample code for java.lang.String definition code for java.lang.String  key, String sample code for java.lang.String definition code for java.lang.String  value)
          Adds a general request property specified by a key-value pair.
abstract  void connect sample code for java.net.URLConnection.connect() definition code for java.net.URLConnection.connect() ()
          Opens a communications link to the resource referenced by this URL, if such a connection has not already been established.
 boolean getAllowUserInteraction sample code for java.net.URLConnection.getAllowUserInteraction() definition code for java.net.URLConnection.getAllowUserInteraction() ()
          Returns the value of the allowUserInteraction field for this object.
 int getConnectTimeout sample code for java.net.URLConnection.getConnectTimeout() definition code for java.net.URLConnection.getConnectTimeout() ()
          Returns setting for connect timeout.
 Object sample code for java.lang.Object definition code for java.lang.Object getContent sample code for java.net.URLConnection.getContent() definition code for java.net.URLConnection.getContent() ()
          Retrieves the contents of this URL connection.
 Object sample code for java.lang.Object definition code for java.lang.Object getContent sample code for java.net.URLConnection.getContent(java.lang.Class[]) definition code for java.net.URLConnection.getContent(java.lang.Class[]) (Class sample code for java.lang.Class definition code for java.lang.Class [] classes)
          Retrieves the contents of this URL connection.
 String sample code for java.lang.String definition code for java.lang.String getContentEncoding sample code for java.net.URLConnection.getContentEncoding() definition code for java.net.URLConnection.getContentEncoding() ()
          Returns the value of the content-encoding header field.
 int getContentLength sample code for java.net.URLConnection.getContentLength() definition code for java.net.URLConnection.getContentLength() ()
          Returns the value of the content-length header field.
 String sample code for java.lang.String definition code for java.lang.String getContentType sample code for java.net.URLConnection.getContentType() definition code for java.net.URLConnection.getContentType() ()
          Returns the value of the content-type header field.
 long getDate sample code for java.net.URLConnection.getDate() definition code for java.net.URLConnection.getDate() ()
          Returns the value of the date header field.
static boolean getDefaultAllowUserInteraction sample code for java.net.URLConnection.getDefaultAllowUserInteraction() definition code for java.net.URLConnection.getDefaultAllowUserInteraction() ()
          Returns the default value of the allowUserInteraction field.
static String sample code for java.lang.String definition code for java.lang.String getDefaultRequestProperty sample code for java.net.URLConnection.getDefaultRequestProperty(java.lang.String) definition code for java.net.URLConnection.getDefaultRequestProperty(java.lang.String) (String sample code for java.lang.String definition code for java.lang.String  key)
          Deprecated. The instance specific getRequestProperty method should be used after an appropriate instance of URLConnection is obtained.
 boolean getDefaultUseCaches sample code for java.net.URLConnection.getDefaultUseCaches() definition code for java.net.URLConnection.getDefaultUseCaches() ()
          Returns the default value of a URLConnection's useCaches flag.
 boolean getDoInput sample code for java.net.URLConnection.getDoInput() definition code for java.net.URLConnection.getDoInput() ()
          Returns the value of this URLConnection's doInput flag.
 boolean getDoOutput sample code for java.net.URLConnection.getDoOutput() definition code for java.net.URLConnection.getDoOutput() ()
          Returns the value of this URLConnection's doOutput flag.
 long getExpiration sample code for java.net.URLConnection.getExpiration() definition code for java.net.URLConnection.getExpiration() ()
          Returns the value of the expires header field.
static FileNameMap sample code for java.net.FileNameMap definition code for java.net.FileNameMap getFileNameMap sample code for java.net.URLConnection.getFileNameMap() definition code for java.net.URLConnection.getFileNameMap() ()
          Loads filename map (a mimetable) from a data file.
 String sample code for java.lang.String definition code for java.lang.String getHeaderField sample code for java.net.URLConnection.getHeaderField(int) definition code for java.net.URLConnection.getHeaderField(int) (int n)
          Returns the value for the nth header field.
 String sample code for java.lang.String definition code for java.lang.String getHeaderField sample code for java.net.URLConnection.getHeaderField(java.lang.String) definition code for java.net.URLConnection.getHeaderField(java.lang.String) (String sample code for java.lang.String definition code for java.lang.String  name)
          Returns the value of the named header field.
 long getHeaderFieldDate sample code for java.net.URLConnection.getHeaderFieldDate(java.lang.String, long) definition code for java.net.URLConnection.getHeaderFieldDate(java.lang.String, long) (String sample code for java.lang.String definition code for java.lang.String  name, long Default)
          Returns the value of the named field parsed as date.
 int getHeaderFieldInt sample code for java.net.URLConnection.getHeaderFieldInt(java.lang.String, int) definition code for java.net.URLConnection.getHeaderFieldInt(java.lang.String, int) (String sample code for java.lang.String definition code for java.lang.String  name, int Default)
          Returns the value of the named field parsed as a number.
 String sample code for java.lang.String definition code for java.lang.String getHeaderFieldKey sample code for java.net.URLConnection.getHeaderFieldKey(int) definition code for java.net.URLConnection.getHeaderFieldKey(int) (int n)
          Returns the key for the nth header field.
 Map sample code for java.util.Map definition code for java.util.Map <String sample code for java.lang.String definition code for java.lang.String ,List sample code for java.util.List definition code for java.util.List <String sample code for java.lang.String definition code for java.lang.String >> getHeaderFields sample code for java.net.URLConnection.getHeaderFields() definition code for java.net.URLConnection.getHeaderFields() ()
          Returns an unmodifiable Map of the header fields.
 long getIfModifiedSince sample code for java.net.URLConnection.getIfModifiedSince() definition code for java.net.URLConnection.getIfModifiedSince() ()
          Returns the value of this object's ifModifiedSince field.
 InputStream sample code for java.io.InputStream definition code for java.io.InputStream getInputStream sample code for java.net.URLConnection.getInputStream() definition code for java.net.URLConnection.getInputStream() ()
          Returns an input stream that reads from this open connection.
 long getLastModified sample code for java.net.URLConnection.getLastModified() definition code for java.net.URLConnection.getLastModified() ()
          Returns the value of the last-modified header field.
 OutputStream sample code for java.io.OutputStream definition code for java.io.OutputStream getOutputStream sample code for java.net.URLConnection.getOutputStream() definition code for java.net.URLConnection.getOutputStream() ()
          Returns an output stream that writes to this connection.
 Permission sample code for java.security.Permission definition code for java.security.Permission getPermission sample code for java.net.URLConnection.getPermission() definition code for java.net.URLConnection.getPermission() ()
          Returns a permission object representing the permission necessary to make the connection represented by this object.
 int getReadTimeout sample code for java.net.URLConnection.getReadTimeout() definition code for java.net.URLConnection.getReadTimeout() ()
          Returns setting for read timeout.
 Map sample code for java.util.Map definition code for java.util.Map <String sample code for java.lang.String definition code for java.lang.String ,List sample code for java.util.List definition code for java.util.List <String sample code for java.lang.String definition code for java.lang.String >> getRequestProperties sample code for java.net.URLConnection.getRequestProperties() definition code for java.net.URLConnection.getRequestProperties() ()
          Returns an unmodifiable Map of general request properties for this connection.
 String sample code for java.lang.String definition code for java.lang.String getRequestProperty sample code for java.net.URLConnection.getRequestProperty(java.lang.String) definition code for java.net.URLConnection.getRequestProperty(java.lang.String) (String sample code for java.lang.String definition code for java.lang.String  key)
          Returns the value of the named general request property for this connection.
 URL sample code for java.net.URL definition code for java.net.URL getURL sample code for java.net.URLConnection.getURL() definition code for java.net.URLConnection.getURL() ()
          Returns the value of this URLConnection's URL field.
 boolean getUseCaches sample code for java.net.URLConnection.getUseCaches() definition code for java.net.URLConnection.getUseCaches() ()
          Returns the value of this URLConnection's useCaches field.
static String sample code for java.lang.String definition code for java.lang.String guessContentTypeFromName sample code for java.net.URLConnection.guessContentTypeFromName(java.lang.String) definition code for java.net.URLConnection.guessContentTypeFromName(java.lang.String) (String sample code for java.lang.String definition code for java.lang.String  fname)
          Tries to determine the content type of an object, based on the specified "file" component of a URL.
static String sample code for java.lang.String definition code for java.lang.String guessContentTypeFromStream sample code for java.net.URLConnection.guessContentTypeFromStream(java.io.InputStream) definition code for java.net.URLConnection.guessContentTypeFromStream(java.io.InputStream) (InputStream sample code for java.io.InputStream definition code for java.io.InputStream  is)
          Tries to determine the type of an input stream based on the characters at the beginning of the input stream.
 void setAllowUserInteraction sample code for java.net.URLConnection.setAllowUserInteraction(boolean) definition code for java.net.URLConnection.setAllowUserInteraction(boolean) (boolean allowuserinteraction)
          Set the value of the allowUserInteraction field of this URLConnection.
 void setConnectTimeout sample code for java.net.URLConnection.setConnectTimeout(int) definition code for java.net.URLConnection.setConnectTimeout(int) (int timeout)
          Sets a specified timeout value, in milliseconds, to be used when opening a communications link to the resource referenced by this URLConnection.
static void setContentHandlerFactory sample code for java.net.URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory) definition code for java.net.URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory) (ContentHandlerFactory sample code for java.net.ContentHandlerFactory definition code for java.net.ContentHandlerFactory  fac)
          Sets the ContentHandlerFactory of an application.
static void setDefaultAllowUserInteraction sample code for java.net.URLConnection.setDefaultAllowUserInteraction(boolean) definition code for java.net.URLConnection.setDefaultAllowUserInteraction(boolean) (boolean defaultallowuserinteraction)
          Sets the default value of the allowUserInteraction field for all future URLConnection objects to the specified value.
static void setDefaultRequestProperty sample code for java.net.URLConnection.setDefaultRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.setDefaultRequestProperty(java.lang.String, java.lang.String) (String sample code for java.lang.String definition code for java.lang.String  key, String sample code for java.lang.String definition code for java.lang.String  value)
          Deprecated. The instance specific setRequestProperty method should be used after an appropriate instance of URLConnection is obtained. Invoking this method will have no effect.
 void setDefaultUseCaches sample code for java.net.URLConnection.setDefaultUseCaches(boolean) definition code for java.net.URLConnection.setDefaultUseCaches(boolean) (boolean defaultusecaches)
          Sets the default value of the useCaches field to the specified value.
 void setDoInput sample code for java.net.URLConnection.setDoInput(boolean) definition code for java.net.URLConnection.setDoInput(boolean) (boolean doinput)
          Sets the value of the doInput field for this URLConnection to the specified value.
 void setDoOutput sample code for java.net.URLConnection.setDoOutput(boolean) definition code for java.net.URLConnection.setDoOutput(boolean) (boolean dooutput)
          Sets the value of the doOutput field for this URLConnection to the specified value.
static void setFileNameMap sample code for java.net.URLConnection.setFileNameMap(java.net.FileNameMap) definition code for java.net.URLConnection.setFileNameMap(java.net.FileNameMap) (FileNameMap sample code for java.net.FileNameMap definition code for java.net.FileNameMap  map)
          Sets the FileNameMap.
 void setIfModifiedSince sample code for java.net.URLConnection.setIfModifiedSince(long) definition code for java.net.URLConnection.setIfModifiedSince(long) (long ifmodifiedsince)
          Sets the value of the ifModifiedSince field of this URLConnection to the specified value.
 void setReadTimeout sample code for java.net.URLConnection.setReadTimeout(int) definition code for java.net.URLConnection.setReadTimeout(int) (int timeout)
          Sets the read timeout to a specified timeout, in milliseconds.
 void setRequestProperty sample code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String) (String sample code for java.lang.String definition code for java.lang.String  key, String sample code for java.lang.String definition code for java.lang.String  value)
          Sets the general request property.
 void setUseCaches sample code for java.net.URLConnection.setUseCaches(boolean) definition code for java.net.URLConnection.setUseCaches(boolean) (boolean usecaches)
          Sets the value of the useCaches field of this URLConnection to the specified value.
 String sample code for java.lang.String definition code for java.lang.String toString sample code for java.net.URLConnection.toString() definition code for java.net.URLConnection.toString() ()
          Returns a String representation of this URL connection.
 
Methods inherited from class java.lang.Object sample code for java.lang.Object definition code for java.lang.Object
clone sample code for java.lang.Object.clone() definition code for java.lang.Object.clone() , equals sample code for java.lang.Object.equals(java.lang.Object) definition code for java.lang.Object.equals(java.lang.Object) , finalize sample code for java.lang.Object.finalize() definition code for java.lang.Object.finalize() , getClass sample code for java.lang.Object.getClass() definition code for java.lang.Object.getClass() , hashCode sample code for java.lang.Object.hashCode() definition code for java.lang.Object.hashCode() , notify sample code for java.lang.Object.notify() definition code for java.lang.Object.notify() , notifyAll sample code for java.lang.Object.notifyAll() definition code for java.lang.Object.notifyAll() , wait sample code for java.lang.Object.wait() definition code for java.lang.Object.wait() , wait sample code for java.lang.Object.wait(long) definition code for java.lang.Object.wait(long) , wait sample code for java.lang.Object.wait(long, int) definition code for java.lang.Object.wait(long, int)
 

Field Detail

url sample code for java.net.URLConnection.url

protected URL sample code for java.net.URL definition code for java.net.URL  url
The URL represents the remote object on the World Wide Web to which this connection is opened.

The value of this field can be accessed by the getURL method.

The default value of this variable is the value of the URL argument in the URLConnection constructor.

See Also:
getURL() sample code for java.net.URLConnection.getURL() definition code for java.net.URLConnection.getURL() , url sample code for java.net.URLConnection.url definition code for java.net.URLConnection.url

doInput sample code for java.net.URLConnection.doInput

protected boolean doInput
This variable is set by the setDoInput method. Its value is returned by the getDoInput method.

A URL connection can be used for input and/or output. Setting the doInput flag to true indicates that the application intends to read data from the URL connection.

The default value of this field is true.

See Also:
getDoInput() sample code for java.net.URLConnection.getDoInput() definition code for java.net.URLConnection.getDoInput() , setDoInput(boolean) sample code for java.net.URLConnection.setDoInput(boolean) definition code for java.net.URLConnection.setDoInput(boolean)

doOutput sample code for java.net.URLConnection.doOutput

protected boolean doOutput
This variable is set by the setDoOutput method. Its value is returned by the getDoOutput method.

A URL connection can be used for input and/or output. Setting the doOutput flag to true indicates that the application intends to write data to the URL connection.

The default value of this field is false.

See Also:
getDoOutput() sample code for java.net.URLConnection.getDoOutput() definition code for java.net.URLConnection.getDoOutput() , setDoOutput(boolean) sample code for java.net.URLConnection.setDoOutput(boolean) definition code for java.net.URLConnection.setDoOutput(boolean)

allowUserInteraction sample code for java.net.URLConnection.allowUserInteraction

protected boolean allowUserInteraction
If true, this URL is being examined in a context in which it makes sense to allow user interactions such as popping up an authentication dialog. If false, then no user interaction is allowed.

The value of this field can be set by the setAllowUserInteraction method. Its value is returned by the getAllowUserInteraction method. Its default value is the value of the argument in the last invocation of the setDefaultAllowUserInteraction method.

See Also:
getAllowUserInteraction() sample code for java.net.URLConnection.getAllowUserInteraction() definition code for java.net.URLConnection.getAllowUserInteraction() , setAllowUserInteraction(boolean) sample code for java.net.URLConnection.setAllowUserInteraction(boolean) definition code for java.net.URLConnection.setAllowUserInteraction(boolean) , setDefaultAllowUserInteraction(boolean) sample code for java.net.URLConnection.setDefaultAllowUserInteraction(boolean) definition code for java.net.URLConnection.setDefaultAllowUserInteraction(boolean)

useCaches sample code for java.net.URLConnection.useCaches

protected boolean useCaches
If true, the protocol is allowed to use caching whenever it can. If false, the protocol must always try to get a fresh copy of the object.

This field is set by the setUseCaches method. Its value is returned by the getUseCaches method.

Its default value is the value given in the last invocation of the setDefaultUseCaches method.

See Also:
setUseCaches(boolean) sample code for java.net.URLConnection.setUseCaches(boolean) definition code for java.net.URLConnection.setUseCaches(boolean) , getUseCaches() sample code for java.net.URLConnection.getUseCaches() definition code for java.net.URLConnection.getUseCaches() , setDefaultUseCaches(boolean) sample code for java.net.URLConnection.setDefaultUseCaches(boolean) definition code for java.net.URLConnection.setDefaultUseCaches(boolean)

ifModifiedSince sample code for java.net.URLConnection.ifModifiedSince

protected long ifModifiedSince
Some protocols support skipping the fetching of the object unless the object has been modified more recently than a certain time.

A nonzero value gives a time as the number of milliseconds since January 1, 1970, GMT. The object is fetched only if it has been modified more recently than that time.

This variable is set by the setIfModifiedSince method. Its value is returned by the getIfModifiedSince method.

The default value of this field is 0, indicating that the fetching must always occur.

See Also:
getIfModifiedSince() sample code for java.net.URLConnection.getIfModifiedSince() definition code for java.net.URLConnection.getIfModifiedSince() , setIfModifiedSince(long) sample code for java.net.URLConnection.setIfModifiedSince(long) definition code for java.net.URLConnection.setIfModifiedSince(long)

connected sample code for java.net.URLConnection.connected

protected boolean connected
If false, this connection object has not created a communications link to the specified URL. If true, the communications link has been established.

Constructor Detail

URLConnection sample code for java.net.URLConnection(java.net.URL) definition code for java.net.URLConnection(java.net.URL)

protected URLConnection(URL sample code for java.net.URL definition code for java.net.URL  url)
Constructs a URL connection to the specified URL. A connection to the object referenced by the URL is not created.

Parameters:
url - the specified URL.
Method Detail

getFileNameMap sample code for java.net.URLConnection.getFileNameMap() definition code for java.net.URLConnection.getFileNameMap()

public static FileNameMap sample code for java.net.FileNameMap definition code for java.net.FileNameMap  getFileNameMap()
Loads filename map (a mimetable) from a data file. It will first try to load the user-specific table, defined by "content.types.user.table" property. If that fails, it tries to load the default built-in table at lib/content-types.properties under java home.

Returns:
the FileNameMap
Since:
1.2
See Also:
setFileNameMap(java.net.FileNameMap) sample code for java.net.URLConnection.setFileNameMap(java.net.FileNameMap) definition code for java.net.URLConnection.setFileNameMap(java.net.FileNameMap)

setFileNameMap sample code for java.net.URLConnection.setFileNameMap(java.net.FileNameMap) definition code for java.net.URLConnection.setFileNameMap(java.net.FileNameMap)

public static void setFileNameMap(FileNameMap sample code for java.net.FileNameMap definition code for java.net.FileNameMap  map)
Sets the FileNameMap.

If there is a security manager, this method first calls the security manager's checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException.

Parameters:
map - the FileNameMap to be set
Throws:
SecurityException sample code for java.lang.SecurityException definition code for java.lang.SecurityException - if a security manager exists and its checkSetFactory method doesn't allow the operation.
Since:
1.2
See Also:
SecurityManager.checkSetFactory() sample code for java.lang.SecurityManager.checkSetFactory() definition code for java.lang.SecurityManager.checkSetFactory() , getFileNameMap() sample code for java.net.URLConnection.getFileNameMap() definition code for java.net.URLConnection.getFileNameMap()

connect sample code for java.net.URLConnection.connect() definition code for java.net.URLConnection.connect()

public abstract void connect()
                      throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Opens a communications link to the resource referenced by this URL, if such a connection has not already been established.

If the connect method is called when the connection has already been opened (indicated by the connected field having the value true), the call is ignored.

URLConnection objects go through two phases: first they are created, then they are connected. After being created, and before being connected, various options can be specified (e.g., doInput and UseCaches). After connecting, it is an error to try to set them. Operations that depend on being connected, like getContentLength, will implicitly perform the connection, if necessary.

Throws:
SocketTimeoutException sample code for java.net.SocketTimeoutException definition code for java.net.SocketTimeoutException - if the timeout expires before the connection can be established
IOException sample code for java.io.IOException definition code for java.io.IOException - if an I/O error occurs while opening the connection.
See Also:
connected sample code for java.net.URLConnection.connected definition code for java.net.URLConnection.connected , getConnectTimeout() sample code for java.net.URLConnection.getConnectTimeout() definition code for java.net.URLConnection.getConnectTimeout() , setConnectTimeout(int) sample code for java.net.URLConnection.setConnectTimeout(int) definition code for java.net.URLConnection.setConnectTimeout(int)

setConnectTimeout sample code for java.net.URLConnection.setConnectTimeout(int) definition code for java.net.URLConnection.setConnectTimeout(int)

public void setConnectTimeout(int timeout)
Sets a specified timeout value, in milliseconds, to be used when opening a communications link to the resource referenced by this URLConnection. If the timeout expires before the connection can be established, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

Some non-standard implmentation of this method may ignore the specified timeout. To see the connect timeout set, please call getConnectTimeout().

Parameters:
timeout - an int that specifies the connect timeout value in milliseconds
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if the timeout parameter is negative
Since:
1.5
See Also:
getConnectTimeout() sample code for java.net.URLConnection.getConnectTimeout() definition code for java.net.URLConnection.getConnectTimeout() , connect() sample code for java.net.URLConnection.connect() definition code for java.net.URLConnection.connect()

getConnectTimeout sample code for java.net.URLConnection.getConnectTimeout() definition code for java.net.URLConnection.getConnectTimeout()

public int getConnectTimeout()
Returns setting for connect timeout.

0 return implies that the option is disabled (i.e., timeout of infinity).

Returns:
an int that indicates the connect timeout value in milliseconds
Since:
1.5
See Also:
setConnectTimeout(int) sample code for java.net.URLConnection.setConnectTimeout(int) definition code for java.net.URLConnection.setConnectTimeout(int) , connect() sample code for java.net.URLConnection.connect() definition code for java.net.URLConnection.connect()

setReadTimeout sample code for java.net.URLConnection.setReadTimeout(int) definition code for java.net.URLConnection.setReadTimeout(int)

public void setReadTimeout(int timeout)
Sets the read timeout to a specified timeout, in milliseconds. A non-zero value specifies the timeout when reading from Input stream when a connection is established to a resource. If the timeout expires before there is data available for read, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

Some non-standard implementation of this method ignores the specified timeout. To see the read timeout set, please call getReadTimeout().

Parameters:
timeout - an int that specifies the timeout value to be used in milliseconds
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if the timeout parameter is negative
Since:
1.5
See Also:
getReadTimeout() sample code for java.net.URLConnection.getReadTimeout() definition code for java.net.URLConnection.getReadTimeout() , InputStream.read() sample code for java.io.InputStream.read() definition code for java.io.InputStream.read()

getReadTimeout sample code for java.net.URLConnection.getReadTimeout() definition code for java.net.URLConnection.getReadTimeout()

public int getReadTimeout()
Returns setting for read timeout. 0 return implies that the option is disabled (i.e., timeout of infinity).

Returns:
an int that indicates the read timeout value in milliseconds
Since:
1.5
See Also:
setReadTimeout(int) sample code for java.net.URLConnection.setReadTimeout(int) definition code for java.net.URLConnection.setReadTimeout(int) , InputStream.read() sample code for java.io.InputStream.read() definition code for java.io.InputStream.read()

getURL sample code for java.net.URLConnection.getURL() definition code for java.net.URLConnection.getURL()

public URL sample code for java.net.URL definition code for java.net.URL  getURL()
Returns the value of this URLConnection's URL field.

Returns:
the value of this URLConnection's URL field.
See Also:
url sample code for java.net.URLConnection.url definition code for java.net.URLConnection.url

getContentLength sample code for java.net.URLConnection.getContentLength() definition code for java.net.URLConnection.getContentLength()

public int getContentLength()
Returns the value of the content-length header field.

Returns:
the content length of the resource that this connection's URL references, or -1 if the content length is not known.

getContentType sample code for java.net.URLConnection.getContentType() definition code for java.net.URLConnection.getContentType()

public String sample code for java.lang.String definition code for java.lang.String  getContentType()
Returns the value of the content-type header field.

Returns:
the content type of the resource that the URL references, or null if not known.
See Also:
getHeaderField(java.lang.String) sample code for java.net.URLConnection.getHeaderField(java.lang.String) definition code for java.net.URLConnection.getHeaderField(java.lang.String)

getContentEncoding sample code for java.net.URLConnection.getContentEncoding() definition code for java.net.URLConnection.getContentEncoding()

public String sample code for java.lang.String definition code for java.lang.String  getContentEncoding()
Returns the value of the content-encoding header field.

Returns:
the content encoding of the resource that the URL references, or null if not known.
See Also:
getHeaderField(java.lang.String) sample code for java.net.URLConnection.getHeaderField(java.lang.String) definition code for java.net.URLConnection.getHeaderField(java.lang.String)

getExpiration sample code for java.net.URLConnection.getExpiration() definition code for java.net.URLConnection.getExpiration()

public long getExpiration()
Returns the value of the expires header field.

Returns:
the expiration date of the resource that this URL references, or 0 if not known. The value is the number of milliseconds since January 1, 1970 GMT.
See Also:
getHeaderField(java.lang.String) sample code for java.net.URLConnection.getHeaderField(java.lang.String) definition code for java.net.URLConnection.getHeaderField(java.lang.String)

getDate sample code for java.net.URLConnection.getDate() definition code for java.net.URLConnection.getDate()

public long getDate()
Returns the value of the date header field.

Returns:
the sending date of the resource that the URL references, or 0 if not known. The value returned is the number of milliseconds since January 1, 1970 GMT.
See Also:
getHeaderField(java.lang.String) sample code for java.net.URLConnection.getHeaderField(java.lang.String) definition code for java.net.URLConnection.getHeaderField(java.lang.String)

getLastModified sample code for java.net.URLConnection.getLastModified() definition code for java.net.URLConnection.getLastModified()

public long getLastModified()
Returns the value of the last-modified header field. The result is the number of milliseconds since January 1, 1970 GMT.

Returns:
the date the resource referenced by this URLConnection was last modified, or 0 if not known.
See Also:
getHeaderField(java.lang.String) sample code for java.net.URLConnection.getHeaderField(java.lang.String) definition code for java.net.URLConnection.getHeaderField(java.lang.String)

getHeaderField sample code for java.net.URLConnection.getHeaderField(java.lang.String) definition code for java.net.URLConnection.getHeaderField(java.lang.String)

public String sample code for java.lang.String definition code for java.lang.String  getHeaderField(String sample code for java.lang.String definition code for java.lang.String  name)
Returns the value of the named header field.

If called on a connection that sets the same header multiple times with possibly different values, only the last value is returned.

Parameters:
name - the name of a header field.
Returns:
the value of the named header field, or null if there is no such field in the header.

getHeaderFields sample code for java.net.URLConnection.getHeaderFields() definition code for java.net.URLConnection.getHeaderFields()

public Map sample code for java.util.Map definition code for java.util.Map <String sample code for java.lang.String definition code for java.lang.String ,List sample code for java.util.List definition code for java.util.List <String sample code for java.lang.String definition code for java.lang.String >> getHeaderFields()
Returns an unmodifiable Map of the header fields. The Map keys are Strings that represent the response-header field names. Each Map value is an unmodifiable List of Strings that represents the corresponding field values.

Returns:
a Map of header fields
Since:
1.4

getHeaderFieldInt sample code for java.net.URLConnection.getHeaderFieldInt(java.lang.String, int) definition code for java.net.URLConnection.getHeaderFieldInt(java.lang.String, int)

public int getHeaderFieldInt(String sample code for java.lang.String definition code for java.lang.String  name,
                             int Default)
Returns the value of the named field parsed as a number.

This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

Parameters:
name - the name of the header field.
Default - the default value.
Returns:
the value of the named field, parsed as an integer. The Default value is returned if the field is missing or malformed.

getHeaderFieldDate sample code for java.net.URLConnection.getHeaderFieldDate(java.lang.String, long) definition code for java.net.URLConnection.getHeaderFieldDate(java.lang.String, long)

public long getHeaderFieldDate(String sample code for java.lang.String definition code for java.lang.String  name,
                               long Default)
Returns the value of the named field parsed as date. The result is the number of milliseconds since January 1, 1970 GMT represented by the named field.

This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

Parameters:
name - the name of the header field.
Default - a default value.
Returns:
the value of the field, parsed as a date. The value of the Default argument is returned if the field is missing or malformed.

getHeaderFieldKey sample code for java.net.URLConnection.getHeaderFieldKey(int) definition code for java.net.URLConnection.getHeaderFieldKey(int)

public String sample code for java.lang.String definition code for java.lang.String  getHeaderFieldKey(int n)
Returns the key for the nth header field. It returns null if there are fewer than n+1 fields.

Parameters:
n - an index, where n>=0
Returns:
the key for the nth header field, or null if there are fewer than n+1 fields.

getHeaderField sample code for java.net.URLConnection.getHeaderField(int) definition code for java.net.URLConnection.getHeaderField(int)

public String sample code for java.lang.String definition code for java.lang.String  getHeaderField(int n)
Returns the value for the nth header field. It returns null if there are fewer than n+1fields.

This method can be used in conjunction with the getHeaderFieldKey sample code for java.net.URLConnection.getHeaderFieldKey(int) definition code for java.net.URLConnection.getHeaderFieldKey(int) method to iterate through all the headers in the message.

Parameters:
n - an index, where n>=0
Returns:
the value of the nth header field or null if there are fewer than n+1 fields
See Also:
getHeaderFieldKey(int) sample code for java.net.URLConnection.getHeaderFieldKey(int) definition code for java.net.URLConnection.getHeaderFieldKey(int)

getContent sample code for java.net.URLConnection.getContent() definition code for java.net.URLConnection.getContent()

public Object sample code for java.lang.Object definition code for java.lang.Object  getContent()
                  throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Retrieves the contents of this URL connection.

This method first determines the content type of the object by calling the getContentType method. If this is the first time that the application has seen that specific content type, a content handler for that content type is created:

  1. If the application has set up a content handler factory instance using the setContentHandlerFactory method, the createContentHandler method of that instance is called with the content type as an argument; the result is a content handler for that content type.
  2. If no content handler factory has yet been set up, or if the factory's createContentHandler method returns null, then the application loads the class named:
             sun.net.www.content.<contentType>
         
    where <contentType> is formed by taking the content-type string, replacing all slash characters with a period ('.'), and all other non-alphanumeric characters with the underscore character '_'. The alphanumeric characters are specifically the 26 uppercase ASCII letters 'A' through 'Z', the 26 lowercase ASCII letters 'a' through 'z', and the 10 ASCII digits '0' through '9'. If the specified class does not exist, or is not a subclass of ContentHandler, then an UnknownServiceException is thrown.

Returns:
the object fetched. The instanceof operator should be used to determine the specific kind of object returned.
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - if an I/O error occurs while getting the content.
UnknownServiceException sample code for java.net.UnknownServiceException definition code for java.net.UnknownServiceException - if the protocol does not support the content type.
See Also:
ContentHandlerFactory.createContentHandler(java.lang.String) sample code for java.net.ContentHandlerFactory.createContentHandler(java.lang.String) definition code for java.net.ContentHandlerFactory.createContentHandler(java.lang.String) , getContentType() sample code for java.net.URLConnection.getContentType() definition code for java.net.URLConnection.getContentType() , setContentHandlerFactory(java.net.ContentHandlerFactory) sample code for java.net.URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory) definition code for java.net.URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory)

getContent sample code for java.net.URLConnection.getContent(java.lang.Class[]) definition code for java.net.URLConnection.getContent(java.lang.Class[])

public Object sample code for java.lang.Object definition code for java.lang.Object  getContent(Class sample code for java.lang.Class definition code for java.lang.Class [] classes)
                  throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Retrieves the contents of this URL connection.

Parameters:
classes - the Class array indicating the requested types
Returns:
the object fetched that is the first match of the type specified in the classes array. null if none of the requested types are supported. The instanceof operator should be used to determine the specific kind of object returned.
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - if an I/O error occurs while getting the content.
UnknownServiceException sample code for java.net.UnknownServiceException definition code for java.net.UnknownServiceException - if the protocol does not support the content type.
See Also:
getContent() sample code for java.net.URLConnection.getContent() definition code for java.net.URLConnection.getContent() , ContentHandlerFactory.createContentHandler(java.lang.String) sample code for java.net.ContentHandlerFactory.createContentHandler(java.lang.String) definition code for java.net.ContentHandlerFactory.createContentHandler(java.lang.String) , getContent(java.lang.Class[]) sample code for java.net.URLConnection.getContent(java.lang.Class[]) definition code for java.net.URLConnection.getContent(java.lang.Class[]) , setContentHandlerFactory(java.net.ContentHandlerFactory) sample code for java.net.URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory) definition code for java.net.URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory)

getPermission sample code for java.net.URLConnection.getPermission() definition code for java.net.URLConnection.getPermission()

public Permission sample code for java.security.Permission definition code for java.security.Permission  getPermission()
                         throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Returns a permission object representing the permission necessary to make the connection represented by this object. This method returns null if no permission is required to make the connection. By default, this method returns java.security.AllPermission. Subclasses should override this method and return the permission that best represents the permission required to make a a connection to the URL. For example, a URLConnection representing a file: URL would return a java.io.FilePermission object.

The permission returned may dependent upon the state of the connection. For example, the permission before connecting may be different from that after connecting. For example, an HTTP sever, say foo.com, may redirect the connection to a different host, say bar.com. Before connecting the permission returned by the connection will represent the permission needed to connect to foo.com, while the permission returned after connecting will be to bar.com.

Permissions are generally used for two purposes: to protect caches of objects obtained through URLConnections, and to check the right of a recipient to learn about a particular URL. In the first case, the permission should be obtained after the object has been obtained. For example, in an HTTP connection, this will represent the permission to connect to the host from which the data was ultimately fetched. In the second case, the permission should be obtained and tested before connecting.

Returns:
the permission object representing the permission necessary to make the connection represented by this URLConnection.
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - if the computation of the permission requires network or file I/O and an exception occurs while computing it.

getInputStream sample code for java.net.URLConnection.getInputStream() definition code for java.net.URLConnection.getInputStream()

public InputStream sample code for java.io.InputStream definition code for java.io.InputStream  getInputStream()
                           throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Returns an input stream that reads from this open connection. A SocketTimeoutException can be thrown when reading from the returned input stream if the read timeout expires before data is available for read.

Returns:
an input stream that reads from this open connection.
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - if an I/O error occurs while creating the input stream.
UnknownServiceException sample code for java.net.UnknownServiceException definition code for java.net.UnknownServiceException - if the protocol does not support input.
See Also:
setReadTimeout(int) sample code for java.net.URLConnection.setReadTimeout(int) definition code for java.net.URLConnection.setReadTimeout(int) , getReadTimeout() sample code for java.net.URLConnection.getReadTimeout() definition code for java.net.URLConnection.getReadTimeout()

getOutputStream sample code for java.net.URLConnection.getOutputStream() definition code for java.net.URLConnection.getOutputStream()

public OutputStream sample code for java.io.OutputStream definition code for java.io.OutputStream  getOutputStream()
                             throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Returns an output stream that writes to this connection.

Returns:
an output stream that writes to this connection.
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - if an I/O error occurs while creating the output stream.
UnknownServiceException sample code for java.net.UnknownServiceException definition code for java.net.UnknownServiceException - if the protocol does not support output.

toString sample code for java.net.URLConnection.toString() definition code for java.net.URLConnection.toString()

public String sample code for java.lang.String definition code for java.lang.String  toString()
Returns a String representation of this URL connection.

Overrides:
toString sample code for java.lang.Object.toString() definition code for java.lang.Object.toString() in class Object sample code for java.lang.Object definition code for java.lang.Object
Returns:
a string representation of this URLConnection.

setDoInput sample code for java.net.URLConnection.setDoInput(boolean) definition code for java.net.URLConnection.setDoInput(boolean)

public void setDoInput(boolean doinput)
Sets the value of the doInput field for this URLConnection to the specified value.

A URL connection can be used for input and/or output. Set the DoInput flag to true if you intend to use the URL connection for input, false if not. The default is true.

Parameters:
doinput - the new value.
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
See Also:
doInput sample code for java.net.URLConnection.doInput definition code for java.net.URLConnection.doInput , getDoInput() sample code for java.net.URLConnection.getDoInput() definition code for java.net.URLConnection.getDoInput()

getDoInput sample code for java.net.URLConnection.getDoInput() definition code for java.net.URLConnection.getDoInput()

public boolean getDoInput()
Returns the value of this URLConnection's doInput flag.

Returns:
the value of this URLConnection's doInput flag.
See Also:
setDoInput(boolean) sample code for java.net.URLConnection.setDoInput(boolean) definition code for java.net.URLConnection.setDoInput(boolean)

setDoOutput sample code for java.net.URLConnection.setDoOutput(boolean) definition code for java.net.URLConnection.setDoOutput(boolean)

public void setDoOutput(boolean dooutput)
Sets the value of the doOutput field for this URLConnection to the specified value.

A URL connection can be used for input and/or output. Set the DoOutput flag to true if you intend to use the URL connection for output, false if not. The default is false.

Parameters:
dooutput - the new value.
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
See Also:
getDoOutput() sample code for java.net.URLConnection.getDoOutput() definition code for java.net.URLConnection.getDoOutput()

getDoOutput sample code for java.net.URLConnection.getDoOutput() definition code for java.net.URLConnection.getDoOutput()

public boolean getDoOutput()
Returns the value of this URLConnection's doOutput flag.

Returns:
the value of this URLConnection's doOutput flag.
See Also:
setDoOutput(boolean) sample code for java.net.URLConnection.setDoOutput(boolean) definition code for java.net.URLConnection.setDoOutput(boolean)

setAllowUserInteraction sample code for java.net.URLConnection.setAllowUserInteraction(boolean) definition code for java.net.URLConnection.setAllowUserInteraction(boolean)

public void setAllowUserInteraction(boolean allowuserinteraction)
Set the value of the allowUserInteraction field of this URLConnection.

Parameters:
allowuserinteraction - the new value.
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
See Also:
getAllowUserInteraction() sample code for java.net.URLConnection.getAllowUserInteraction() definition code for java.net.URLConnection.getAllowUserInteraction()

getAllowUserInteraction sample code for java.net.URLConnection.getAllowUserInteraction() definition code for java.net.URLConnection.getAllowUserInteraction()

public boolean getAllowUserInteraction()
Returns the value of the allowUserInteraction field for this object.

Returns:
the value of the allowUserInteraction field for this object.
See Also:
setAllowUserInteraction(boolean) sample code for java.net.URLConnection.setAllowUserInteraction(boolean) definition code for java.net.URLConnection.setAllowUserInteraction(boolean)

setDefaultAllowUserInteraction sample code for java.net.URLConnection.setDefaultAllowUserInteraction(boolean) definition code for java.net.URLConnection.setDefaultAllowUserInteraction(boolean)

public static void setDefaultAllowUserInteraction(boolean defaultallowuserinteraction)
Sets the default value of the allowUserInteraction field for all future URLConnection objects to the specified value.

Parameters:
defaultallowuserinteraction - the new value.
See Also:
getDefaultAllowUserInteraction() sample code for java.net.URLConnection.getDefaultAllowUserInteraction() definition code for java.net.URLConnection.getDefaultAllowUserInteraction()

getDefaultAllowUserInteraction sample code for java.net.URLConnection.getDefaultAllowUserInteraction() definition code for java.net.URLConnection.getDefaultAllowUserInteraction()

public static boolean getDefaultAllowUserInteraction()
Returns the default value of the allowUserInteraction field.

Ths default is "sticky", being a part of the static state of all URLConnections. This flag applies to the next, and all following URLConnections that are created.

Returns:
the default value of the allowUserInteraction field.
See Also:
setDefaultAllowUserInteraction(boolean) sample code for java.net.URLConnection.setDefaultAllowUserInteraction(boolean) definition code for java.net.URLConnection.setDefaultAllowUserInteraction(boolean)

setUseCaches sample code for java.net.URLConnection.setUseCaches(boolean) definition code for java.net.URLConnection.setUseCaches(boolean)

public void setUseCaches(boolean usecaches)
Sets the value of the useCaches field of this URLConnection to the specified value.

Some protocols do caching of documents. Occasionally, it is important to be able to "tunnel through" and ignore the caches (e.g., the "reload" button in a browser). If the UseCaches flag on a connection is true, the connection is allowed to use whatever caches it can. If false, caches are to be ignored. The default value comes from DefaultUseCaches, which defaults to true.

Parameters:
usecaches - a boolean indicating whether or not to allow caching
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
See Also:
getUseCaches() sample code for java.net.URLConnection.getUseCaches() definition code for java.net.URLConnection.getUseCaches()

getUseCaches sample code for java.net.URLConnection.getUseCaches() definition code for java.net.URLConnection.getUseCaches()

public boolean getUseCaches()
Returns the value of this URLConnection's useCaches field.

Returns:
the value of this URLConnection's useCaches field.
See Also:
setUseCaches(boolean) sample code for java.net.URLConnection.setUseCaches(boolean) definition code for java.net.URLConnection.setUseCaches(boolean)

setIfModifiedSince sample code for java.net.URLConnection.setIfModifiedSince(long) definition code for java.net.URLConnection.setIfModifiedSince(long)

public void setIfModifiedSince(long ifmodifiedsince)
Sets the value of the ifModifiedSince field of this URLConnection to the specified value.

Parameters:
ifmodifiedsince - the new value.
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
See Also:
getIfModifiedSince() sample code for java.net.URLConnection.getIfModifiedSince() definition code for java.net.URLConnection.getIfModifiedSince()

getIfModifiedSince sample code for java.net.URLConnection.getIfModifiedSince() definition code for java.net.URLConnection.getIfModifiedSince()

public long getIfModifiedSince()
Returns the value of this object's ifModifiedSince field.

Returns:
the value of this object's ifModifiedSince field.
See Also:
setIfModifiedSince(long) sample code for java.net.URLConnection.setIfModifiedSince(long) definition code for java.net.URLConnection.setIfModifiedSince(long)

getDefaultUseCaches sample code for java.net.URLConnection.getDefaultUseCaches() definition code for java.net.URLConnection.getDefaultUseCaches()

public boolean getDefaultUseCaches()
Returns the default value of a URLConnection's useCaches flag.

Ths default is "sticky", being a part of the static state of all URLConnections. This flag applies to the next, and all following URLConnections that are created.

Returns:
the default value of a URLConnection's useCaches flag.
See Also:
setDefaultUseCaches(boolean) sample code for java.net.URLConnection.setDefaultUseCaches(boolean) definition code for java.net.URLConnection.setDefaultUseCaches(boolean)

setDefaultUseCaches sample code for java.net.URLConnection.setDefaultUseCaches(boolean) definition code for java.net.URLConnection.setDefaultUseCaches(boolean)

public void setDefaultUseCaches(boolean defaultusecaches)
Sets the default value of the useCaches field to the specified value.

Parameters:
defaultusecaches - the new value.
See Also:
getDefaultUseCaches() sample code for java.net.URLConnection.getDefaultUseCaches() definition code for java.net.URLConnection.getDefaultUseCaches()

setRequestProperty sample code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String)

public void setRequestProperty(String sample code for java.lang.String definition code for java.lang.String  key,
                               String sample code for java.lang.String definition code for java.lang.String  value)
Sets the general request property. If a property with the key already exists, overwrite its value with the new value.

NOTE: HTTP requires all request properties which can legally have multiple instances with the same key to use a comma-seperated list syntax which enables multiple properties to be appended into a single property.

Parameters:
key - the keyword by which the request is known (e.g., "accept").
value - the value associated with it.
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - if key is null
See Also:
getRequestProperty(java.lang.String) sample code for java.net.URLConnection.getRequestProperty(java.lang.String) definition code for java.net.URLConnection.getRequestProperty(java.lang.String)

addRequestProperty sample code for java.net.URLConnection.addRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.addRequestProperty(java.lang.String, java.lang.String)

public void addRequestProperty(String sample code for java.lang.String definition code for java.lang.String  key,
                               String sample code for java.lang.String definition code for java.lang.String  value)
Adds a general request property specified by a key-value pair. This method will not overwrite existing values associated with the same key.

Parameters:
key - the keyword by which the request is known (e.g., "accept").
value - the value associated with it.
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - if key is null
Since:
1.4
See Also:
getRequestProperties() sample code for java.net.URLConnection.getRequestProperties() definition code for java.net.URLConnection.getRequestProperties()

getRequestProperty sample code for java.net.URLConnection.getRequestProperty(java.lang.String) definition code for java.net.URLConnection.getRequestProperty(java.lang.String)

public String sample code for java.lang.String definition code for java.lang.String  getRequestProperty(String sample code for java.lang.String definition code for java.lang.String  key)
Returns the value of the named general request property for this connection.

Parameters:
key - the keyword by which the request is known (e.g., "accept").
Returns:
the value of the named general request property for this connection. If key is null, then null is returned.
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
See Also:
setRequestProperty(java.lang.String, java.lang.String) sample code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String)

getRequestProperties sample code for java.net.URLConnection.getRequestProperties() definition code for java.net.URLConnection.getRequestProperties()

public Map sample code for java.util.Map definition code for java.util.Map <String sample code for java.lang.String definition code for java.lang.String ,List sample code for java.util.List definition code for java.util.List <String sample code for java.lang.String definition code for java.lang.String >> getRequestProperties()
Returns an unmodifiable Map of general request properties for this connection. The Map keys are Strings that represent the request-header field names. Each Map value is a unmodifiable List of Strings that represents the corresponding field values.

Returns:
a Map of the general request properties for this connection.
Throws:
IllegalStateException sample code for java.lang.IllegalStateException definition code for java.lang.IllegalStateException - if already connected
Since:
1.4

setDefaultRequestProperty sample code for java.net.URLConnection.setDefaultRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.setDefaultRequestProperty(java.lang.String, java.lang.String)

@Deprecated
public static void setDefaultRequestProperty(String sample code for java.lang.String definition code for java.lang.String  key,
                                                        String sample code for java.lang.String definition code for java.lang.String  value)
Deprecated. The instance specific setRequestProperty method should be used after an appropriate instance of URLConnection is obtained. Invoking this method will have no effect.

Sets the default value of a general request property. When a URLConnection is created, it is initialized with these properties.

Parameters:
key - the keyword by which the request is known (e.g., "accept").
value - the value associated with the key.
See Also:
setRequestProperty(java.lang.String,java.lang.String) sample code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.setRequestProperty(java.lang.String, java.lang.String) , getDefaultRequestProperty(java.lang.String) sample code for java.net.URLConnection.getDefaultRequestProperty(java.lang.String) definition code for java.net.URLConnection.getDefaultRequestProperty(java.lang.String)

getDefaultRequestProperty sample code for java.net.URLConnection.getDefaultRequestProperty(java.lang.String) definition code for java.net.URLConnection.getDefaultRequestProperty(java.lang.String)

@Deprecated
public static String sample code for java.lang.String definition code for java.lang.String  getDefaultRequestProperty(String sample code for java.lang.String definition code for java.lang.String  key)
Deprecated. The instance specific getRequestProperty method should be used after an appropriate instance of URLConnection is obtained.

Returns the value of the default request property. Default request properties are set for every connection.

Parameters:
key - the keyword by which the request is known (e.g., "accept").
Returns:
the value of the default request property for the specified key.
See Also:
getRequestProperty(java.lang.String) sample code for java.net.URLConnection.getRequestProperty(java.lang.String) definition code for java.net.URLConnection.getRequestProperty(java.lang.String) , setDefaultRequestProperty(java.lang.String, java.lang.String) sample code for java.net.URLConnection.setDefaultRequestProperty(java.lang.String, java.lang.String) definition code for java.net.URLConnection.setDefaultRequestProperty(java.lang.String, java.lang.String)

setContentHandlerFactory sample code for java.net.URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory) definition code for java.net.URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory)

public static void setContentHandlerFactory(ContentHandlerFactory sample code for java.net.ContentHandlerFactory definition code for java.net.ContentHandlerFactory  fac)
Sets the ContentHandlerFactory of an application. It can be called at most once by an application.

The ContentHandlerFactory instance is used to construct a content handler from a content type

If there is a security manager, this method first calls the security manager's checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException.

Parameters:
fac - the desired factory.
Throws:
Error sample code for java.lang.Error definition code for java.lang.Error - if the factory has already been defined.
SecurityException sample code for java.lang.SecurityException definition code for java.lang.SecurityException - if a security manager exists and its checkSetFactory method doesn't allow the operation.
See Also:
ContentHandlerFactory sample code for java.net.ContentHandlerFactory definition code for java.net.ContentHandlerFactory , getContent() sample code for java.net.URLConnection.getContent() definition code for java.net.URLConnection.getContent() , SecurityManager.checkSetFactory() sample code for java.lang.SecurityManager.checkSetFactory() definition code for java.lang.SecurityManager.checkSetFactory()

guessContentTypeFromName sample code for java.net.URLConnection.guessContentTypeFromName(java.lang.String) definition code for java.net.URLConnection.guessContentTypeFromName(java.lang.String)

public static String sample code for java.lang.String definition code for java.lang.String  guessContentTypeFromName(String sample code for java.lang.String definition code for java.lang.String  fname)
Tries to determine the content type of an object, based on the specified "file" component of a URL. This is a convenience method that can be used by subclasses that override the getContentType method.

Parameters:
fname - a filename.
Returns:
a guess as to what the content type of the object is, based upon its file name.
See Also:
getContentType() sample code for java.net.URLConnection.getContentType() definition code for java.net.URLConnection.getContentType()

guessContentTypeFromStream sample code for java.net.URLConnection.guessContentTypeFromStream(java.io.InputStream) definition code for java.net.URLConnection.guessContentTypeFromStream(java.io.InputStream)

public static String sample code for java.lang.String definition code for java.lang.String  guessContentTypeFromStream(InputStream sample code for java.io.InputStream definition code for java.io.InputStream  is)
                                         throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Tries to determine the type of an input stream based on the characters at the beginning of the input stream. This method can be used by subclasses that override the getContentType method.

Ideally, this routine would not be needed. But many http servers return the incorrect content type; in addition, there are many nonstandard extensions. Direct inspection of the bytes to determine the content type is often more accurate than believing the content type claimed by the http server.

Parameters:
is - an input stream that supports marks.
Returns:
a guess at the content type, or null if none can be determined.
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - if an I/O error occurs while reading the input stream.
See Also:
InputStream.mark(int) sample code for java.io.InputStream.mark(int) definition code for java.io.InputStream.mark(int) , InputStream.markSupported() sample code for java.io.InputStream.markSupported() definition code for java.io.InputStream.markSupported() , getContentType() sample code for java.net.URLConnection.getContentType() definition code for java.net.URLConnection.getContentType()