java.io
Class PrintWriter

java.lang.Object   
  java.io.Writer   
      java.io.PrintWriter

All Implemented Interfaces:

Closeable , Flushable , Appendable

public class PrintWriter
extends Writer   

Print formatted representations of objects to a text-output stream. This class implements all of the print methods found in PrintStream . It does not contain methods for writing raw bytes, for which a program should use unencoded byte streams.

Unlike the PrintStream class, if automatic flushing is enabled it will be done only when one of the println, printf, or format methods is invoked, rather than whenever a newline character happens to be output. These methods use the platform's own notion of line separator rather than the newline character.

Methods in this class never throw I/O exceptions, although some of its constructors may. The client may inquire as to whether any errors have occurred by invoking checkError() .

Since:

JDK1.1

Field Summary

protected Writer

out The underlying character-output stream of this PrintWriter.

Fields inherited from class java.io.Writer

lock

Constructor Summary

PrintWriter (File file)
Creates a new PrintWriter, without automatic line flushing, with the specified file.

PrintWriter (File file, String csn)
Creates a new PrintWriter, without automatic line flushing, with the specified file and charset.

PrintWriter (OutputStream out)
Create a new PrintWriter, without automatic line flushing, from an existing OutputStream.

PrintWriter (OutputStream out, boolean autoFlush)
Create a new PrintWriter from an existing OutputStream.

PrintWriter (String fileName)
Creates a new PrintWriter, without automatic line flushing, with the specified file name.

PrintWriter (String fileName, String csn)
Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset.

PrintWriter (Writer out)
Create a new PrintWriter, without automatic line flushing.

PrintWriter (Writer out, boolean autoFlush)
Create a new PrintWriter.

Method Summary

PrintWriter	append (char c) Appends the specified character to this writer.
PrintWriter	append (CharSequence csq) Appends the specified character sequence to this writer.
PrintWriter	append (CharSequence csq, int start, int end) Appends a subsequence of the specified character sequence to this writer.
boolean	checkError () Flush the stream if it's not closed and check its error state.
void	close () Close the stream.
void	flush () Flush the stream.
PrintWriter	format (Locale l, String format, Object ... args) Writes a formatted string to this writer using the specified format string and arguments.
PrintWriter	format (String format, Object ... args) Writes a formatted string to this writer using the specified format string and arguments.
void	print (boolean b) Print a boolean value.
void	print (char c) Print a character.
void	print (char[] s) Print an array of characters.
void	print (double d) Print a double-precision floating-point number.
void	print (float f) Print a floating-point number.
void	print (int i) Print an integer.
void	print (long l) Print a long integer.
void	print (Object obj) Print an object.
void	print (String s) Print a string.
PrintWriter	printf (Locale l, String format, Object ... args) A convenience method to write a formatted string to this writer using the specified format string and arguments.
PrintWriter	printf (String format, Object ... args) A convenience method to write a formatted string to this writer using the specified format string and arguments.
void	println () Terminate the current line by writing the line separator string.
void	println (boolean x) Print a boolean value and then terminate the line.
void	println (char x) Print a character and then terminate the line.
void	println (char[] x) Print an array of characters and then terminate the line.
void	println (double x) Print a double-precision floating-point number and then terminate the line.
void	println (float x) Print a floating-point number and then terminate the line.
void	println (int x) Print an integer and then terminate the line.
void	println (long x) Print a long integer and then terminate the line.
void	println (Object x) Print an Object and then terminate the line.
void	println (String x) Print a String and then terminate the line.
protected void	setError () Indicate that an error has occurred.
void	write (char[] buf) Write an array of characters.
void	write (char[] buf, int off, int len) Write A Portion of an array of characters.
void	write (int c) Write a single character.
void	write (String s) Write a string.
void	write (String s, int off, int len) Write a portion of a string.

Methods inherited from class java.lang.Object

clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait

Field Detail

out

protected Writer    out

The underlying character-output stream of this PrintWriter.

Since:

1.2

Constructor Detail

PrintWriter

public PrintWriter(Writer    out)

Create a new PrintWriter, without automatic line flushing.

Parameters:

out - A character-output stream

PrintWriter

public PrintWriter(Writer    out,
                   boolean autoFlush)

Create a new PrintWriter.

Parameters:

out - A character-output stream

autoFlush - A boolean; if true, the println, printf, or format methods will flush the output buffer

PrintWriter

public PrintWriter(OutputStream    out)

Create a new PrintWriter, without automatic line flushing, from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding.

Parameters:

out - An output stream

See Also:

OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)

PrintWriter

public PrintWriter(OutputStream    out,
                   boolean autoFlush)

Create a new PrintWriter from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding.

Parameters:

out - An output stream

autoFlush - A boolean; if true, the println, printf, or format methods will flush the output buffer

See Also:

OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)

PrintWriter

public PrintWriter(String    fileName)
            throws FileNotFoundException   

Creates a new PrintWriter, without automatic line flushing, with the specified file name. This convenience constructor creates the necessary intermediate OutputStreamWriter , which will encode characters using the default charset for this instance of the Java virtual machine.

Parameters:

fileName - The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.

Throws:

FileNotFoundException - If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

SecurityException - If a security manager is present and checkWrite(fileName) denies write access to the file

Since:

1.5

PrintWriter

public PrintWriter(String    fileName,
                   String    csn)
            throws FileNotFoundException   ,
                   UnsupportedEncodingException   

Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset. This convenience constructor creates the necessary intermediate OutputStreamWriter , which will encode characters using the provided charset.

Parameters:

fileName - The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.

csn - The name of a supported charset

Throws:

FileNotFoundException - If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

SecurityException - If a security manager is present and checkWrite(fileName) denies write access to the file

UnsupportedEncodingException - If the named charset is not supported

Since:

1.5

PrintWriter

public PrintWriter(File    file)
            throws FileNotFoundException   

Creates a new PrintWriter, without automatic line flushing, with the specified file. This convenience constructor creates the necessary intermediate OutputStreamWriter , which will encode characters using the default charset for this instance of the Java virtual machine.

Parameters:

file - The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.

Throws:

FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

SecurityException - If a security manager is present and checkWrite(file.getPath()) denies write access to the file

Since:

1.5

PrintWriter

public PrintWriter(File    file,
                   String    csn)
            throws FileNotFoundException   ,
                   UnsupportedEncodingException   

Creates a new PrintWriter, without automatic line flushing, with the specified file and charset. This convenience constructor creates the necessary intermediate OutputStreamWriter , which will encode characters using the provided charset.

Parameters:

file - The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.

csn - The name of a supported charset

Throws:

FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

SecurityException - If a security manager is present and checkWrite(file.getPath()) denies write access to the file

UnsupportedEncodingException - If the named charset is not supported

Since:

1.5

Method Detail

flush

public void flush()

Flush the stream.

Specified by:

flush in interface Flushable

Specified by:

flush in class Writer

See Also:

checkError()

close

public void close()

Close the stream.

Specified by:

close in interface Closeable

Specified by:

close in class Writer

See Also:

checkError()

checkError

public boolean checkError()

Flush the stream if it's not closed and check its error state. Errors are cumulative; once the stream encounters an error, this routine will return true on all successive calls.

Returns:

True if the print stream has encountered an error, either on the underlying output stream or during a format conversion.

setError

protected void setError()

Indicate that an error has occurred.

write

public void write(int c)

Write a single character.

Overrides:

write in class Writer

Parameters:

c - int specifying a character to be written.

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