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")));
Summary
Inherited fields |
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Public constructors | |
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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 | |
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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 | |
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Public constructors
BufferedWriter
public BufferedWriter (Writer out)
Creates a buffered character-output stream that uses a default-sized output buffer.
Parameters | |
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out |
Writer : A Writer |
BufferedWriter
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 | |
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IllegalArgumentException |
If sz <= 0 |
Public methods
close
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 | |
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IOException |
flush
public void flush ()
Flushes the stream.
Throws | |
---|---|
IOException |
If an I/O error occurs |
newLine
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
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
public void write (String s, int off, int len)
Writes a portion of a String.
Implementation Requirements:
- While the specification of this method in the
superclass
recommends that an
IndexOutOfBoundsException
be thrown iflen
is negative oroff + len
is negative, the implementation in this class does not throw such an exception in these cases but instead simply writes no characters.
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 | |
---|---|
IndexOutOfBoundsException |
If off is negative,
or off + len is greater than the length
of the given string |
IOException |
If an I/O error occurs |
write
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
BufferedWriter
s 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 | |
---|---|
IndexOutOfBoundsException |
If off is negative, or len is negative,
or off + len is negative or greater than the length
of the given array |
IOException |
If an I/O error occurs |