Reads the requested number of bytes from the input stream into the given byte array. This method blocks until
len
bytes of input data have been read, end of stream is detected, or an exception is thrown. The number of bytes actually read, possibly zero, is returned. This method does not close the input stream.
In the case where end of stream is reached before len
bytes have been read, then the actual number of bytes read will be returned. When this stream reaches end of stream, further invocations of this method will return zero.
If len
is zero, then no bytes are read and 0
is returned; otherwise, there is an attempt to read up to len
bytes.
The first byte read is stored into element b[off]
, the next one in to 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 b[off]
through b[off+
k-1]
, leaving elements b[off+
k]
through b[off+len-1]
unaffected.
The behavior for the case where the input stream is asynchronously closed , or the thread interrupted during the read, is highly input stream specific, and therefore not specified.
If an I/O error occurs reading from the input stream, then it may do so after some, but not all, bytes of b
have been updated with data from the input stream. Consequently the input stream and b
may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.