GeezerVison is showing docs.oracle.com — BufferedWriter (Java SE 25 & JDK 25)
Class BufferedWriter
- All Implemented Interfaces:
Closeable, Flushable, Appendable, AutoCloseable
public class BufferedWriter
extends Writer
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.
- API Note:
- Once wrapped in a
BufferedWriter, the underlying
Writer should not be used directly nor wrapped with
another writer.
- Since:
- 1.1
- See Also:
-
-
-
Constructor Summary
Constructors
Constructor
Description
Creates a buffered character-output stream that uses a default-sized
output buffer.
Creates a new buffered character-output stream that uses an output
buffer of the given size.
-
Method Summary
Modifier and Type
Method
Description
void
Closes the stream, flushing it first.
void
void
void
write(char[] cbuf,
int off,
int len)
Writes a portion of an array of characters.
void
Writes a single character.
void
Writes a portion of a String.
Methods declared in class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
-
Constructor Details
-
BufferedWriter
public BufferedWriter(Writer out)
Creates a buffered character-output stream that uses a default-sized
output buffer.
- Parameters:
out - 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 - A Writersz - Output-buffer size, a positive integer- Throws:
IllegalArgumentException - If sz <= 0
-
Method Details
-
write
Writes a single character.
- Overrides:
write in class Writer- Parameters:
c - int specifying a character to be written- Throws:
IOException - If an I/O error occurs
-
write
public void write(char[] cbuf,
int off,
int len)
throws IOException
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.
- Specified by:
write in class Writer- Parameters:
cbuf - A character arrayoff - Offset from which to start reading characterslen - 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 arrayIOException - If an I/O error occurs
-
write
Writes a portion of a String.
- Overrides:
write in class Writer- Implementation Requirements:
- While the specification of this method in the
superclass
recommends that an
IndexOutOfBoundsException be thrown
if len is negative or off + 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 to be writtenoff - Offset from which to start reading characterslen - Number of characters to be written- Throws:
IndexOutOfBoundsException - If off is negative,
or off + len is greater than the length
of the given stringIOException - If an I/O error occurs
-
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
-
-
close
Description copied from class: Writer
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.
- Specified by:
close in interface AutoCloseable- Specified by:
close in interface Closeable- Specified by:
close in class Writer- Throws:
IOException - If an I/O error occurs
|