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BufferedWriter

public class BufferedWriter
extends Writer

java.lang.Object
   ↳ java.io.Writer
     ↳ java.io.BufferedWriter


Writes text to a character-output stream, buffering characters so as to provide for the efficient writing of single characters, arrays, and strings.

The buffer size may be specified, or the default size may be accepted. The default is large enough for most purposes.

A newLine() method is provided, which uses the platform's own notion of line separator as defined by the system property line.separator. Not all platforms use the newline character ('\n') to terminate lines. Calling this method to terminate each output line is therefore preferred to writing a newline character directly.

In general, a Writer sends its output immediately to the underlying character or byte stream. Unless prompt output is required, it is advisable to wrap a BufferedWriter around any Writer whose write() operations may be costly, such as FileWriters and OutputStreamWriters. For example,

 PrintWriter out
   = new PrintWriter(new BufferedWriter(new FileWriter("foo.out")));
 
will buffer the PrintWriter's output to the file. Without buffering, each invocation of a print() method would cause characters to be converted into bytes that would then be written immediately to the file, which can be very inefficient.

Summary

Inherited fields

Public constructors

BufferedWriter(Writer out)

Creates a buffered character-output stream that uses a default-sized output buffer.

BufferedWriter(Writer out, int sz)

Creates a new buffered character-output stream that uses an output buffer of the given size.

Public methods

void close()

Closes the stream, flushing it first.

void flush()

Flushes the stream.

void newLine()

Writes a line separator.

void write(int c)

Writes a single character.

void write(String s, int off, int len)

Writes a portion of a String.

void write(char[] cbuf, int off, int len)

Writes a portion of an array of characters.

Inherited methods

Public constructors

BufferedWriter

added in API level 1
public BufferedWriter (Writer out)

Creates a buffered character-output stream that uses a default-sized output buffer.

Parameters
out Writer: A Writer

BufferedWriter

added in API level 1
public BufferedWriter (Writer out, 
                int sz)

Creates a new buffered character-output stream that uses an output buffer of the given size.

Parameters
out Writer: A Writer

sz int: Output-buffer size, a positive integer

Throws
IllegalArgumentException If sz <= 0

Public methods

close

added in API level 1
public void close ()

Closes the stream, flushing it first. Once the stream has been closed, further write() or flush() invocations will cause an IOException to be thrown. Closing a previously closed stream has no effect.

Throws
IOException

flush

added in API level 1
public void flush ()

Flushes the stream.

Throws
IOException If an I/O error occurs

newLine

added in API level 1
public void newLine ()

Writes a line separator. The line separator string is defined by the system property line.separator, and is not necessarily a single newline ('\n') character.

Throws
IOException If an I/O error occurs

write

added in API level 1
public void write (int c)

Writes a single character.

Parameters
c int: int specifying a character to be written

Throws
IOException If an I/O error occurs

write

added in API level 1
public void write (String s, 
                int off, 
                int len)

Writes a portion of a String.

If the value of the len parameter is negative then no characters are written. This is contrary to the specification of this method in the superclass, which requires that an IndexOutOfBoundsException be thrown.

Parameters
s String: String to be written

off int: Offset from which to start reading characters

len int: Number of characters to be written

Throws
IOException If an I/O error occurs

write

added in API level 1
public void write (char[] cbuf, 
                int off, 
                int len)

Writes a portion of an array of characters.

Ordinarily this method stores characters from the given array into this stream's buffer, flushing the buffer to the underlying stream as needed. If the requested length is at least as large as the buffer, however, then this method will flush the buffer and write the characters directly to the underlying stream. Thus redundant BufferedWriters will not copy data unnecessarily.

Parameters
cbuf char: A character array

off int: Offset from which to start reading characters

len int: Number of characters to write

Throws
IOException If an I/O error occurs