程序包 java.io

类 InputStreamReader

java.lang.Object

java.io.Reader

java.io.InputStreamReader

所有已实现的接口:

Closeable, AutoCloseable, Readable

直接已知子类:

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));
 

从以下版本开始:

JDK1.1

另请参阅:

BufferedReader, InputStream, Charset

字段概要

从类继承的字段 java.io.Reader

lock

构造器概要

构造器

构造器	说明
InputStreamReader(InputStream in)	Creates an InputStreamReader that uses the default charset.
InputStreamReader(InputStream in, String charsetName)	Creates an InputStreamReader that uses the named 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.

方法概要

限定符和类型	方法	说明
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.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

从类继承的方法 java.io.Reader

mark, markSupported, read, read, reset, skip

构造器详细资料

InputStreamReader

public InputStreamReader(InputStream in)

Creates an InputStreamReader that uses the default charset.

参数:

in - An InputStream

InputStreamReader

public InputStreamReader(InputStream in,
                         String charsetName)
                  throws UnsupportedEncodingException

Creates an InputStreamReader that uses the named charset.

参数:

in - An InputStream

charsetName - The name of a supported charset

抛出:

UnsupportedEncodingException - If the named charset is not supported

InputStreamReader

public InputStreamReader(InputStream in,
                         Charset cs)

Creates an InputStreamReader that uses the given charset.

参数:

in - An InputStream

cs - A charset

从以下版本开始:

1.4

InputStreamReader

public InputStreamReader(InputStream in,
                         CharsetDecoder dec)

Creates an InputStreamReader that uses the given charset decoder.

参数:

in - An InputStream

dec - A charset decoder

从以下版本开始:

1.4

方法详细资料

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(java.io.InputStream,java.lang.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.

返回:

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

另请参阅:

Charset

read

public int read()
         throws IOException

Reads a single character.

覆盖:

read 在类中 Reader

返回:

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

抛出:

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.

指定者:

read 在类中 Reader

参数:

cbuf - Destination buffer

offset - Offset at which to start storing characters

length - Maximum number of characters to read

返回:

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

抛出:

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.

覆盖:

ready 在类中 Reader

返回:

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.

抛出:

IOException - If an I/O error occurs

close

public void close()
           throws IOException

从类复制的说明: 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.

指定者:

close 在接口中 AutoCloseable

指定者:

close 在接口中 Closeable

指定者:

close 在类中 Reader

抛出:

IOException - If an I/O error occurs