public
class
InputStreamReader
extends Reader
| java.lang.Object | ||
| ↳ | java.io.Reader | |
| ↳ | java.io.InputStreamReader | |
 Known Direct Subclasses
|
An InputStreamReader is a bridge from byte streams to character streams: It
reads bytes and decodes them into characters using a specified 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));
See also:
Inherited fields |
|---|
From
class
java.io.Reader
|
Public constructors | |
|---|---|
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. |
|
Public methods | |
|---|---|
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. |
Inherited methods | |
|---|---|
From
class
java.io.Reader
| |
From
class
java.lang.Object
| |
From
interface
java.lang.Readable
| |
From
interface
java.io.Closeable
| |
From
interface
java.lang.AutoCloseable
| |
InputStreamReader (InputStream in)
Creates an InputStreamReader that uses the default charset.
| Parameters | |
|---|---|
in |
InputStream:
An InputStream
|
InputStreamReader (InputStream in, String charsetName)
Creates an InputStreamReader that uses the named charset.
| Parameters | |
|---|---|
in |
InputStream:
An InputStream |
charsetName |
String:
The name of a supported
|
| Throws | |
|---|---|
UnsupportedEncodingException |
If the named charset is not supported |
InputStreamReader (InputStream in, Charset cs)
Creates an InputStreamReader that uses the given charset.
| Parameters | |
|---|---|
in |
InputStream:
An InputStream |
cs |
Charset:
A charset |
InputStreamReader (InputStream in, CharsetDecoder dec)
Creates an InputStreamReader that uses the given charset decoder.
| Parameters | |
|---|---|
in |
InputStream:
An InputStream |
dec |
CharsetDecoder:
A charset decoder |
void close ()
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.
| Throws | |
|---|---|
IOException |
|
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 | |
|---|---|
String |
The historical name of this encoding, or
null if the stream has been closed |
See also:
int read ()
Reads a single character.
| Returns | |
|---|---|
int |
The character read, or -1 if the end of the stream has been reached |
| Throws | |
|---|---|
IOException |
If an I/O error occurs |
Developers
int read (char[] cbuf,
int offset,
int length)
Reads characters into a portion of an array.
| Parameters | |
|---|---|
cbuf |
char:
Destination buffer |
offset |
int:
Offset at which to start storing characters |
length |
int:
Maximum number of characters to read |
| Returns | |
|---|---|
int |
The number of characters read, or -1 if the end of the stream has been reached |
| Throws | |
|---|---|
IOException |
If an I/O error occurs |
boolean ready ()
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.
| Returns | |
|---|---|
boolean |
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 |