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Java™ Platform Standard Ed. 6 |
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java.lang.Object java.io.Reader java.io.InputStreamReader
public class InputStreamReader
An InputStreamReader is a bridge from byte streams to character streams: It
reads bytes and decodes them into characters using a specified
. The charset that it uses
may be specified by name or may be given explicitly, or the platform's
default charset may be accepted.
charset
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));
BufferedReader
,
InputStream
,
Charset
Field Summary |
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Fields inherited from class java.io.Reader |
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lock |
Constructor Summary | |
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InputStreamReader(InputStream in)
Creates an InputStreamReader that uses the default charset. |
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InputStreamReader(InputStream in,
Charset cs)
Creates an InputStreamReader that uses the given charset. |
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InputStreamReader(InputStream in,
CharsetDecoder dec)
Creates an InputStreamReader that uses the given charset decoder. |
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InputStreamReader(InputStream in,
String charsetName)
Creates an InputStreamReader that uses the named charset. |
Method Summary | |
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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 |
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mark, markSupported, read, read, reset, skip |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public InputStreamReader(InputStream in)
in
- An InputStreampublic InputStreamReader(InputStream in, String charsetName) throws UnsupportedEncodingException
in
- An InputStreamcharsetName
- The name of a supported
charset
UnsupportedEncodingException
- If the named charset is not supportedpublic InputStreamReader(InputStream in, Charset cs)
in
- An InputStreamcs
- A charsetpublic InputStreamReader(InputStream in, CharsetDecoder dec)
in
- An InputStreamdec
- A charset decoderMethod Detail |
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public String getEncoding()
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.
null
if the stream has been closedCharset
public int read() throws IOException
read
in class Reader
IOException
- If an I/O error occurspublic int read(char[] cbuf, int offset, int length) throws IOException
read
in class Reader
cbuf
- Destination bufferoffset
- Offset at which to start storing characterslength
- Maximum number of characters to read
IOException
- If an I/O error occurspublic boolean ready() throws IOException
ready
in class Reader
IOException
- If an I/O error occurspublic void close() throws IOException
Reader
close
in interface Closeable
close
in class Reader
IOException
- If an I/O error occurs
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Java™ Platform Standard Ed. 6 |
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