- java.lang.Object
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- java.io.Writer
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- java.io.BufferedWriter
 
 
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- 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.
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Constructor SummaryConstructors Constructor Description 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.
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Method SummaryAll Methods Instance Methods Concrete Methods Modifier and Type Method Description voidflush()Flushes the stream.voidnewLine()Writes a line separator.voidwrite(char[] cbuf, int off, int len)Writes a portion of an array of characters.voidwrite(int c)Writes a single character.voidwrite(String s, int off, int len)Writes a portion of a String.
 
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Constructor Detail- 
BufferedWriterpublic BufferedWriter(Writer out) Creates a buffered character-output stream that uses a default-sized output buffer.- Parameters:
- out- A Writer
 
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BufferedWriterpublic BufferedWriter(Writer out, int sz) Creates a new buffered character-output stream that uses an output buffer of the given size.- Parameters:
- out- A Writer
- sz- Output-buffer size, a positive integer
- Throws:
- IllegalArgumentException- If- sz <= 0
 
 
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Method Detail- 
writepublic void write(int c) throws IOExceptionWrites a single character.- Overrides:
- writein class- Writer
- Parameters:
- c- int specifying a character to be written
- Throws:
- IOException- If an I/O error occurs
 
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writepublic void write(char[] cbuf, int off, int len) throws IOExceptionWrites 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:
- writein class- Writer
- Parameters:
- cbuf- A character array
- off- Offset from which to start reading characters
- len- Number of characters to write
- Throws:
- IndexOutOfBoundsException- If- offis negative, or- lenis negative, or- off + lenis negative or greater than the length of the given array
- IOException- If an I/O error occurs
 
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writepublic void write(String s, int off, int len) throws IOException Writes a portion of a String.- Overrides:
- writein class- Writer
- Implementation Requirements:
- While the specification of this method in the
 superclass
 recommends that an IndexOutOfBoundsExceptionbe thrown iflenis negative oroff + lenis 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 written
- off- Offset from which to start reading characters
- len- Number of characters to be written
- Throws:
- IndexOutOfBoundsException- If- offis negative, or- off + lenis greater than the length of the given string
- IOException- If an I/O error occurs
 
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newLinepublic void newLine() throws IOExceptionWrites a line separator. The line separator string is defined by the system propertyline.separator, and is not necessarily a single newline ('\n') character.- Throws:
- IOException- If an I/O error occurs
 
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flushpublic void flush() throws IOExceptionFlushes the stream.- Specified by:
- flushin interface- Flushable
- Specified by:
- flushin class- Writer
- Throws:
- IOException- If an I/O error occurs
 
 
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