|Constructor and Description|
|Modifier and Type||Method and Description|
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.
Closes this input stream and releases any system resources associated with the stream.
Reads the next byte of data from the input stream.
Reads up to
public int read() throws IOException
intin the range
255. If no byte is available because the end of the stream has been reached, the value
-1is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.
A subclass must provide an implementation of this method.
public int read(byte b, int off, int len) throws IOException
lenbytes of data from the input stream into an array of bytes. An attempt is made to read as many as
lenbytes, but a smaller number may be read. The number of bytes actually read is returned as an integer.
This method blocks until input data is available, end of file is detected, or an exception is thrown.
len is zero, then no bytes are read and
0 is returned; otherwise, there is an attempt to read at
least one byte. If no byte is available because the stream is at end of
file, the value
-1 is returned; otherwise, at least one
byte is read and stored into
The first byte read is stored into element
next one into
b[off+1], and so on. The number of bytes read
is, at most, equal to
len. Let k be the number of
bytes actually read; these bytes will be stored in elements
In every case, elements
b[off] and elements
b[b.length-1] are unaffected.
InputStream simply calls the method
read() repeatedly. If the first such call results in an
IOException, that exception is returned from the call to
len) method. If
any subsequent call to
read() results in a
IOException, the exception is caught and treated as if it
were end of file; the bytes read up to that point are stored into
b and the number of bytes read before the exception
occurred is returned. The default implementation of this method blocks
until the requested amount of input data
len has been read,
end of file is detected, or an exception is thrown. Subclasses are encouraged
to provide a more efficient implementation of this method.
b- the buffer into which the data is read.
off- the start offset in array
bat which the data is written.
len- the maximum number of bytes to read.
-1if there is no more data because the end of the stream has been reached.
IOException- If the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other I/O error occurs.
public void close() throws IOException
close method of
public int available() throws IOException
Note that while some implementations of
InputStream will return
the total number of bytes in the stream, many will not. It is
never correct to use the return value of this method to allocate
a buffer intended to hold all data in this stream.
available method for class
This method should be overridden by subclasses.