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StringReader (Java Platform SE 6) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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java.io
Class StringReader

java.lang.Object
  java.io.Reader
      java.io.StringReader

All Implemented Interfaces:

Closeable, Readable

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public class StringReader
extends Reader

A character stream whose source is a string.

Since:

JDK1.1

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Field Summary

 

Fields inherited from class java.io.Reader
lock

 

Constructor Summary
StringReader(String s)           Creates a new string reader.

 

Method Summary
void	close()           Closes the stream and releases any system resources associated with it.
void	mark(int readAheadLimit)           Marks the present position in the stream.
boolean	markSupported()           Tells whether this stream supports the mark() operation, which it does.
int	read()           Reads a single character.
int	read(char[] cbuf, int off, int len)           Reads characters into a portion of an array.
boolean	ready()           Tells whether this stream is ready to be read.
void	reset()           Resets the stream to the most recent mark, or to the beginning of the string if it has never been marked.
long	skip(long ns)           Skips the specified number of characters in the stream.

 

Methods inherited from class java.io.Reader
read, read

 

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Constructor Detail

StringReader

public StringReader(String s)

Creates a new string reader.

Parameters:

s - String providing the character stream.

Method Detail

read

public int read()
         throws IOException

Reads a single character.

Overrides:

read in class Reader

Returns:

The character read, or -1 if the end of the stream has been reached

Throws:

IOException - If an I/O error occurs

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read

public int read(char[] cbuf,
                int off,
                int len)
         throws IOException

Reads characters into a portion of an array.

Specified by:

read in class Reader

Parameters:

cbuf - Destination buffer

off - Offset at which to start writing characters

len - Maximum number of characters to read

Returns:

The number of characters read, or -1 if the end of the stream has been reached

Throws:

IOException - If an I/O error occurs

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skip

public long skip(long ns)
          throws IOException

Skips the specified number of characters in the stream. Returns the number of characters that were skipped.

The ns parameter may be negative, even though the skip method of the Reader superclass throws an exception in this case. Negative values of ns cause the stream to skip backwards. Negative return values indicate a skip backwards. It is not possible to skip backwards past the beginning of the string.

If the entire string has been read or skipped, then this method has no effect and always returns 0.

Overrides:

skip in class Reader

Parameters:

ns - The number of characters to skip

Returns:

The number of characters actually skipped

Throws:

IOException - If an I/O error occurs

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ready

public boolean ready()
              throws IOException

Tells whether this stream is ready to be read.

Overrides:

ready in class Reader

Returns:

True if the next read() is guaranteed not to block for input

Throws:

IOException - If the stream is closed

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markSupported

public boolean markSupported()

Tells whether this stream supports the mark() operation, which it does.

Overrides:

markSupported in class Reader

Returns:

true if and only if this stream supports the mark operation.

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mark

public void mark(int readAheadLimit)
          throws IOException

Marks the present position in the stream. Subsequent calls to reset() will reposition the stream to this point.

Overrides:

mark in class Reader

Parameters:

readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. Because the stream's input comes from a string, there is no actual limit, so this argument must not be negative, but is otherwise ignored.

Throws:

IllegalArgumentException - If readAheadLimit is < 0

IOException - If an I/O error occurs

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reset

public void reset()
           throws IOException

Resets the stream to the most recent mark, or to the beginning of the string if it has never been marked.

Overrides:

reset in class Reader

Throws:

IOException - If an I/O error occurs

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close

public void close()

Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously closed stream has no effect.

Specified by:

close in interface Closeable

Specified by:

close in class Reader

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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