当前页面: 在线文档首页 > JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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

---

Overview  Package   Class  Use  Tree  Deprecated  Index  Help		Java™ Platform Standard Ed. 6
PREV CLASS   NEXT CLASS	FRAMES    NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

---

java.io
Class InputStreamReader

java.lang.Object
  java.io.Reader
      java.io.InputStreamReader

All Implemented Interfaces:

Closeable, Readable

Direct Known Subclasses:

FileReader

---

public class InputStreamReader
extends Reader

An InputStreamReader is a bridge from byte streams to character streams: It reads bytes and decodes them into characters using a specified charset. The charset that it uses may be specified by name or may be given explicitly, or the platform's default charset may be accepted.

Each invocation of one of an InputStreamReader's read() methods may cause one or more bytes to be read from the underlying byte-input stream. To enable the efficient conversion of bytes to characters, more bytes may be read ahead from the underlying stream than are necessary to satisfy the current read operation.

For top efficiency, consider wrapping an InputStreamReader within a BufferedReader. For example:

 BufferedReader in
   = new BufferedReader(new InputStreamReader(System.in));
 

Since:

JDK1.1

See Also:

BufferedReader, InputStream, Charset

---

Field Summary

 

Fields inherited from class java.io.Reader
lock

 

Constructor Summary
InputStreamReader(InputStream in)           Creates an InputStreamReader that uses the default charset.
InputStreamReader(InputStream in, Charset cs)           Creates an InputStreamReader that uses the given charset.
InputStreamReader(InputStream in, CharsetDecoder dec)           Creates an InputStreamReader that uses the given charset decoder.
InputStreamReader(InputStream in, String charsetName)           Creates an InputStreamReader that uses the named charset.

 

Method Summary
void	close()           Closes the stream and releases any system resources associated with it.
String	getEncoding()           Returns the name of the character encoding being used by this stream.
int	read()           Reads a single character.
int	read(char[] cbuf, int offset, int length)           Reads characters into a portion of an array.
boolean	ready()           Tells whether this stream is ready to be read.

 

Methods inherited from class java.io.Reader
mark, markSupported, read, read, reset, skip

 

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

 

Constructor Detail

InputStreamReader

public InputStreamReader(InputStream in)

Creates an InputStreamReader that uses the default charset.

Parameters:

in - An InputStream

---

InputStreamReader

public InputStreamReader(InputStream in,
                         String charsetName)
                  throws UnsupportedEncodingException

Creates an InputStreamReader that uses the named charset.

Parameters:

in - An InputStream

charsetName - The name of a supported charset

Throws:

UnsupportedEncodingException - If the named charset is not supported

---

InputStreamReader

public InputStreamReader(InputStream in,
                         Charset cs)

Creates an InputStreamReader that uses the given charset.

Parameters:

in - An InputStream

cs - A charset

Since:

1.4

---

InputStreamReader

public InputStreamReader(InputStream in,
                         CharsetDecoder dec)

Creates an InputStreamReader that uses the given charset decoder.

Parameters:

in - An InputStream

dec - A charset decoder

Since:

1.4

Method Detail

getEncoding

public String getEncoding()

Returns the name of the character encoding being used by this stream.

If the encoding has an historical name then that name is returned; otherwise the encoding's canonical name is returned.

If this instance was created with the InputStreamReader(InputStream, String) constructor then the returned name, being unique for the encoding, may differ from the name passed to the constructor. This method will return null if the stream has been closed.

Returns:

The historical name of this encoding, or null if the stream has been closed

See Also:

Charset

---

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

---

read

public int read(char[] cbuf,
                int offset,
                int length)
         throws IOException

Reads characters into a portion of an array.

Specified by:

read in class Reader

Parameters:

cbuf - Destination buffer

offset - Offset at which to start storing characters

length - 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

---

ready

public boolean ready()
              throws IOException

Tells whether this stream is ready to be read. An InputStreamReader is ready if its input buffer is not empty, or if bytes are available to be read from the underlying byte stream.

Overrides:

ready in class Reader

Returns:

True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

Throws:

IOException - If an I/O error occurs

---

close

public void close()
           throws IOException

Description copied from class: Reader

Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() 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

Throws:

IOException - If an I/O error occurs

---

Overview  Package   Class  Use  Tree  Deprecated  Index  Help		Java™ Platform Standard Ed. 6
PREV CLASS   NEXT CLASS	FRAMES    NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

---

Submit a bug or feature
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.

Copyright 2006 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.