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));
BufferedReader
, InputStream
, Charset
lock
public InputStreamReader(InputStream in)
Creates an InputStreamReader that uses the default charset.
in
- An InputStreampublic InputStreamReader(InputStream in, String charsetName) throws UnsupportedEncodingException
Creates an InputStreamReader that uses the named charset.
in
- An InputStreamcharsetName
- The name of a supported charset
UnsupportedEncodingException
- If the named charset is not supportedpublic InputStreamReader(InputStream in, Charset cs)
Creates an InputStreamReader that uses the given charset.
in
- An InputStreamcs
- A charsetpublic InputStreamReader(InputStream in, CharsetDecoder dec)
Creates an InputStreamReader that uses the given charset decoder.
in
- An InputStreamdec
- A charset decoderpublic 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.
null
if the stream has been closedCharset
public int read() throws IOException
Reads a single character.
read
in class Reader
IOException
- If an I/O error occurspublic int read(char[] cbuf, int offset, int length) throws IOException
Reads characters into a portion of an array.
read
in class Reader
cbuf
- Destination bufferoffset
- Offset at which to start storing characterslength
- Maximum number of characters to readIOException
- If an I/O error occurspublic 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.
ready
in class Reader
IOException
- If an I/O error occurspublic 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.
close
in interface Closeable
close
in interface AutoCloseable
close
in class Reader
IOException
- If an I/O error occurs
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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