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Since: API Level 1

public class

PrintWriter

extends Writer

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

Class Overview

Wraps either an existing OutputStream or an existing Writer and provides convenience methods for printing common data types in a human readable format. No IOException is thrown by this class. Instead, callers should use checkError() to see if a problem has occurred in this writer.

Summary

Fields
protected Writer	out	The writer to print data to.

[Expand]

Inherited Fields

From class java.io.Writer

Public Constructors
	PrintWriter(OutputStream out) Constructs a new `PrintWriter` with `out` as its target stream.
	PrintWriter(OutputStream out, boolean autoFlush) Constructs a new `PrintWriter` with `out` as its target stream.
	PrintWriter(Writer wr) Constructs a new `PrintWriter` with `wr` as its target writer.
	PrintWriter(Writer wr, boolean autoFlush) Constructs a new `PrintWriter` with `out` as its target writer.
	PrintWriter(File file) Constructs a new `PrintWriter` with `file` as its target.
	PrintWriter(File file, String csn) Constructs a new `PrintWriter` with `file` as its target.
	PrintWriter(String fileName) Constructs a new `PrintWriter` with the file identified by `fileName` as its target.
	PrintWriter(String fileName, String csn) Constructs a new `PrintWriter` with the file identified by `fileName` as its target.

Public Methods
PrintWriter	append(char c) Appends the character `c` to the target.
PrintWriter	append(CharSequence csq, int start, int end) Appends a subsequence of the character sequence `csq` to the target.
PrintWriter	append(CharSequence csq) Appends the character sequence `csq` to the target.
boolean	checkError() Flushes this writer and returns the value of the error flag.
void	close() Closes this print writer.
void	flush() Ensures that all pending data is sent out to the target.
PrintWriter	format(Locale l, String format, Object... args) Writes a string formatted by an intermediate `Formatter` to the target using the specified locale, format string and arguments.
PrintWriter	format(String format, Object... args) Formats `args` according to the format string `format`, and writes the result to this stream.
void	print(float fnum) Prints the string representation of the specified float to the target.
void	print(double dnum) Prints the string representation of the specified double to the target.
void	print(String str) Prints a string to the target.
void	print(Object obj) Prints the string representation of the specified object to the target.
void	print(char ch) Prints the string representation of the specified character to the target.
void	print(char[] charArray) Prints the string representation of the specified character array to the target.
void	print(long lnum) Prints the string representation of the specified long to the target.
void	print(int inum) Prints the string representation of the specified integer to the target.
void	print(boolean bool) Prints the string representation of the specified boolean to the target.
PrintWriter	printf(Locale l, String format, Object... args) Prints a formatted string.
PrintWriter	printf(String format, Object... args) Prints a formatted string.
void	println() Prints a newline.
void	println(float f) Prints the string representation of the float `f` followed by a newline.
void	println(int i) Prints the string representation of the int `i` followed by a newline.
void	println(long l) Prints the string representation of the long `l` followed by a newline.
void	println(Object obj) Prints the string representation of the object `o`, or `"null`, followed by a newline.
void	println(char[] chars) Prints the string representation of the character array `chars` followed by a newline.
void	println(String str) Prints the string representation of the string `s` followed by a newline.
void	println(char c) Prints the string representation of the char `c` followed by a newline.
void	println(double d) Prints the string representation of the double `d` followed by a newline.
void	println(boolean b) Prints the string representation of the boolean `b` followed by a newline.
void	write(char[] buf, int offset, int count) Writes `count` characters from `buffer` starting at `offset` to the target.
void	write(int oneChar) Writes one character to the target.
void	write(char[] buf) Writes the character buffer `buf` to the target.
void	write(String str, int offset, int count) Writes `count` characters from `str` starting at `offset` to the target.
void	write(String str) Writes the characters from the specified string to the target.

Protected Methods
void	clearError() Sets the error state of the stream to false.
void	setError() Sets the error flag of this writer to true.

[Expand]

Inherited Methods

From class java.io.Writer

Writer	append(CharSequence csq) Appends the character sequence `csq` to the target.
Writer	append(CharSequence csq, int start, int end) Appends a subsequence of the character sequence `csq` to the target.
Writer	append(char c) Appends the character `c` to the target.
abstract void	close() Closes this writer.
abstract void	flush() Flushes this writer.
void	write(char[] buf) Writes the entire character buffer `buf` to the target.
void	write(String str) Writes the characters from the specified string to the target.
abstract void	write(char[] buf, int offset, int count) Writes `count` characters starting at `offset` in `buf` to the target.
void	write(String str, int offset, int count) Writes `count` characters from `str` starting at `offset` to the target.
void	write(int oneChar) Writes one character to the target.

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of `Class` that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

From interface java.io.Closeable

From interface java.io.Flushable

From interface java.lang.Appendable

Fields

protected Writer out

Since: API Level 1

The writer to print data to.

Public Constructors

public PrintWriter (OutputStream out)

Since: API Level 1

Constructs a new PrintWriter with out as its target stream. By default, the new print writer does not automatically flush its contents to the target stream when a newline is encountered.

Parameters

out	the target output stream.

Throws

NullPointerException	if `out` is `null`.

public PrintWriter (OutputStream out, boolean autoFlush)

Since: API Level 1

Constructs a new PrintWriter with out as its target stream. The parameter autoFlush determines if the print writer automatically flushes its contents to the target stream when a newline is encountered.

Parameters

out	the target output stream.
autoFlush	indicates whether contents are flushed upon encountering a newline sequence.

Throws

NullPointerException	if `out` is `null`.

public PrintWriter (Writer wr)

Since: API Level 1

Constructs a new PrintWriter with wr as its target writer. By default, the new print writer does not automatically flush its contents to the target writer when a newline is encountered.

Parameters

wr	the target writer.

Throws

NullPointerException	if `wr` is `null`.

public PrintWriter (Writer wr, boolean autoFlush)

Since: API Level 1

Constructs a new PrintWriter with out as its target writer. The parameter autoFlush determines if the print writer automatically flushes its contents to the target writer when a newline is encountered.

Parameters

wr	the target writer.
autoFlush	indicates whether to flush contents upon encountering a newline sequence.

Throws

NullPointerException	if `out` is `null`.

public PrintWriter (File file)

Since: API Level 1

Constructs a new PrintWriter with file as its target. The VM's default character set is used for character encoding. The print writer does not automatically flush its contents to the target file when a newline is encountered. The output to the file is buffered.

Parameters

file	the target file. If the file already exists, its contents are removed, otherwise a new file is created.

Throws

FileNotFoundException	if an error occurs while opening or creating the target file.

public PrintWriter (File file, String csn)

Since: API Level 1

Constructs a new PrintWriter with file as its target. The character set named csn is used for character encoding. The print writer does not automatically flush its contents to the target file when a newline is encountered. The output to the file is buffered.

Parameters

file	the target file. If the file already exists, its contents are removed, otherwise a new file is created.
csn	the name of the character set used for character encoding.

Throws

FileNotFoundException	if an error occurs while opening or creating the target file.
NullPointerException	if `csn` is `null`.
UnsupportedEncodingException	if the encoding specified by `csn` is not supported.

public PrintWriter (String fileName)

Since: API Level 1

Constructs a new PrintWriter with the file identified by fileName as its target. The VM's default character set is used for character encoding. The print writer does not automatically flush its contents to the target file when a newline is encountered. The output to the file is buffered.

Parameters

fileName	the target file's name. If the file already exists, its contents are removed, otherwise a new file is created.

Throws

FileNotFoundException	if an error occurs while opening or creating the target file.

public PrintWriter (String fileName, String csn)

Since: API Level 1

Constructs a new PrintWriter with the file identified by fileName as its target. The character set named csn is used for character encoding. The print writer does not automatically flush its contents to the target file when a newline is encountered. The output to the file is buffered.

Parameters

fileName	the target file's name. If the file already exists, its contents are removed, otherwise a new file is created.
csn	the name of the character set used for character encoding.

Throws

FileNotFoundException	if an error occurs while opening or creating the target file.
NullPointerException	if `csn` is `null`.
UnsupportedEncodingException	if the encoding specified by `csn` is not supported.

Public Methods

public PrintWriter append (char c)

Since: API Level 1

Appends the character c to the target.

Parameters

c	the character to append to the target.

Returns

this writer.

public PrintWriter append (CharSequence csq, int start, int end)

Since: API Level 1

Appends a subsequence of the character sequence csq to the target. This method works the same way as PrintWriter.print(csq.subsequence(start, end).toString()). If csq is null, then the specified subsequence of the string "null" will be written to the target.

Parameters

csq	the character sequence appended to the target.
start	the index of the first char in the character sequence appended to the target.
end	the index of the character following the last character of the subsequence appended to the target.

Returns

this writer.

Throws

StringIndexOutOfBoundsException	if `start > end`, `start < 0`, `end < 0` or either `start` or `end` are greater or equal than the length of `csq`.

public PrintWriter append (CharSequence csq)

Since: API Level 1

Appends the character sequence csq to the target. This method works the same way as PrintWriter.print(csq.toString()). If csq is null, then the string "null" is written to the target.

Parameters

csq	the character sequence appended to the target.

Returns

this writer.

public boolean checkError ()

Since: API Level 1

Flushes this writer and returns the value of the error flag.

Returns

true if either an IOException has been thrown previously or if setError() has been called; false otherwise.

public void close ()

Since: API Level 1

Closes this print writer. Flushes this writer and then closes the target. If an I/O error occurs, this writer's error flag is set to true.

public void flush ()

Since: API Level 1

Ensures that all pending data is sent out to the target. It also flushes the target. If an I/O error occurs, this writer's error state is set to true.

public PrintWriter format (Locale l, String format, Object... args)

Since: API Level 1

Writes a string formatted by an intermediate Formatter to the target using the specified locale, format string and arguments. If automatic flushing is enabled then this writer is flushed.

Parameters

l	the locale used in the method. No localization will be applied if `l` is `null`.
format	the format string (see `format(String, Object...)`)
args	the list of arguments passed to the formatter. If there are more arguments than required by `format`, additional arguments are ignored.

Returns

this writer.

Throws

IllegalFormatException	if the format string is illegal or incompatible with the arguments, if there are not enough arguments or if any other error regarding the format string or arguments is detected.
NullPointerException	if `format == null`

public PrintWriter format (String format, Object... args)

Since: API Level 1

Formats args according to the format string format, and writes the result to this stream. This method uses the user's default locale. See "Be wary of the default locale". If automatic flushing is enabled then the buffer is flushed as well.

Parameters

format	the format string (see `format(String, Object...)`)
args	the list of arguments passed to the formatter. If there are more arguments than required by `format`, additional arguments are ignored.

Returns

this writer.

Throws

IllegalFormatException	if the format string is illegal or incompatible with the arguments, if there are not enough arguments or if any other error regarding the format string or arguments is detected.
NullPointerException	if `format == null`

public void print (float fnum)

Since: API Level 1

Prints the string representation of the specified float to the target.

Parameters

fnum	the float value to print to the target.

public void print (double dnum)

Since: API Level 1

Prints the string representation of the specified double to the target.

Parameters

dnum	the double value to print to the target.

public void print (String str)

Since: API Level 1

Prints a string to the target. The string is converted to an array of bytes using the encoding chosen during the construction of this writer. The bytes are then written to the target with write(int).

If an I/O error occurs, this writer's error flag is set to true.

Parameters

str	the string to print to the target.

public void print (Object obj)

Since: API Level 1

Prints the string representation of the specified object to the target.

Parameters

obj	the object to print to the target.

public void print (char ch)

Since: API Level 1

Prints the string representation of the specified character to the target.

Parameters

ch	the character to print to the target.

public void print (char[] charArray)

Since: API Level 1

Prints the string representation of the specified character array to the target.

Parameters

charArray	the character array to print to the target.

public void print (long lnum)

Since: API Level 1

Prints the string representation of the specified long to the target.

Parameters

lnum	the long value to print to the target.

public void print (int inum)

Since: API Level 1

Prints the string representation of the specified integer to the target.

Parameters

inum	the integer value to print to the target.

public void print (boolean bool)

Since: API Level 1

Prints the string representation of the specified boolean to the target.

Parameters

bool	the boolean value to print the target.

public PrintWriter printf (Locale l, String format, Object... args)

Since: API Level 1

Prints a formatted string. The behavior of this method is the same as this writer's #format(Locale, String, Object...) method.

Parameters

l	the locale used in the method. No localization will be applied if `l` is `null`.
format	the format string (see `format(String, Object...)`)
args	the list of arguments passed to the formatter. If there are more arguments than required by `format`, additional arguments are ignored.

Returns

this writer.

Throws

IllegalFormatException	if the format string is illegal or incompatible with the arguments, if there are not enough arguments or if any other error regarding the format string or arguments is detected.
NullPointerException	if `format == null`

public PrintWriter printf (String format, Object... args)

Since: API Level 1

Prints a formatted string. The behavior of this method is the same as this writer's #format(String, Object...) method.

The Locale used is the user's default locale. See "Be wary of the default locale".

Parameters

format	the format string (see `format(String, Object...)`)
args	the list of arguments passed to the formatter. If there are more arguments than required by `format`, additional arguments are ignored.

Returns

this writer.

Throws

IllegalFormatException	if the format string is illegal or incompatible with the arguments, if there are not enough arguments or if any other error regarding the format string or arguments is detected.
NullPointerException	if `format == null`

public void println ()

Since: API Level 1

Prints a newline. Flushes this writer if the autoFlush flag is set to true.

public void println (float f)

Since: API Level 1

Prints the string representation of the float f followed by a newline. Flushes this writer if the autoFlush flag is set to true.

public void println (int i)

Since: API Level 1

Prints the string representation of the int i followed by a newline. Flushes this writer if the autoFlush flag is set to true.

public void println (long l)

Since: API Level 1

Prints the string representation of the long l followed by a newline. Flushes this writer if the autoFlush flag is set to true.

public void println (Object obj)

Since: API Level 1

Prints the string representation of the object o, or "null, followed by a newline. Flushes this writer if the autoFlush flag is set to true.

public void println (char[] chars)

Since: API Level 1

Prints the string representation of the character array chars followed by a newline. Flushes this writer if the autoFlush flag is set to true.

public void println (String str)

Since: API Level 1

Prints the string representation of the string s followed by a newline. Flushes this writer if the autoFlush flag is set to true.

The string is converted to an array of bytes using the encoding chosen during the construction of this writer. The bytes are then written to the target with write(int). Finally, this writer is flushed if the autoFlush flag is set to true.

If an I/O error occurs, this writer's error flag is set to true.

public void println (char c)

Since: API Level 1

Prints the string representation of the char c followed by a newline. Flushes this writer if the autoFlush flag is set to true.

public void println (double d)

Since: API Level 1

Prints the string representation of the double d followed by a newline. Flushes this writer if the autoFlush flag is set to true.

public void println (boolean b)

Since: API Level 1

Prints the string representation of the boolean b followed by a newline. Flushes this writer if the autoFlush flag is set to true.

public void write (char[] buf, int offset, int count)

Since: API Level 1

Writes count characters from buffer starting at offset to the target.

This writer's error flag is set to true if this writer is closed or an I/O error occurs.

Parameters

buf	the buffer to write to the target.
offset	the index of the first character in `buffer` to write.
count	the number of characters in `buffer` to write.

Throws

IndexOutOfBoundsException	if `offset < 0` or `count < 0`, or if `offset + count` is greater than the length of `buf`.

public void write (int oneChar)

Since: API Level 1

Writes one character to the target. Only the two least significant bytes of the integer oneChar are written.

This writer's error flag is set to true if this writer is closed or an I/O error occurs.

Parameters

oneChar	the character to write to the target.

public void write (char[] buf)

Since: API Level 1

Writes the character buffer buf to the target.

Parameters

buf	the non-null array containing characters to write.

public void write (String str, int offset, int count)

Since: API Level 1

Writes count characters from str starting at offset to the target.

Parameters

str	the non-null string containing the characters to write.
offset	the index of the first character in `str` to write.
count	the number of characters from `str` to write.

Throws

IndexOutOfBoundsException	if `offset < 0` or `count < 0`, or if `offset + count` is greater than the length of `str`.

public void write (String str)

Since: API Level 1

Writes the characters from the specified string to the target.

Parameters

str	the non-null string containing the characters to write.

Protected Methods

protected void clearError ()

Since: API Level 9

Sets the error state of the stream to false.

protected void setError ()

Since: API Level 1

Sets the error flag of this writer to true.

Results

Interfaces

Classes

Exceptions

Errors

PrintWriter

Class Overview

Summary

Fields

protected Writer out

Public Constructors

public PrintWriter (OutputStream out)

Parameters

Throws

public PrintWriter (OutputStream out, boolean autoFlush)

Parameters

Throws

public PrintWriter (Writer wr)

Parameters

Throws

public PrintWriter (Writer wr, boolean autoFlush)

Parameters

Throws

public PrintWriter (File file)

Parameters

Throws

public PrintWriter (File file, String csn)

Parameters

Throws

public PrintWriter (String fileName)

Parameters

Throws

public PrintWriter (String fileName, String csn)

Parameters

Throws

Public Methods

public PrintWriter append (char c)

Parameters

Returns

public PrintWriter append (CharSequence csq, int start, int end)

Parameters

Returns

Throws

public PrintWriter append (CharSequence csq)

Parameters

Returns

public boolean checkError ()

Returns

See Also

public void close ()

public void flush ()

public PrintWriter format (Locale l, String format, Object... args)

Parameters

Returns

Throws

public PrintWriter format (String format, Object... args)

Parameters

Returns

Throws

public void print (float fnum)

Parameters

See Also

public void print (double dnum)

Parameters

See Also

public void print (String str)

Parameters

See Also

public void print (Object obj)

Parameters

See Also

public void print (char ch)

Parameters

See Also

public void print (char[] charArray)

Parameters

See Also

public void print (long lnum)

Parameters

See Also