read
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. I n 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 boff, the next one in to boff+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 boff through boff+k-1, leaving elements boff+k through boff+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.
Return
The total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
Parameters
The buffer into which the data is read.
The start offset in the destination array b.
The maximum number of bytes read.
Throws
If an I/O error occurs.
if b is null.
if off is negative, len is negative, or len is greater than b.length - off
Reads up to a specified number of bytes from the input stream. This method reads until the requested number of bytes has been read, end of stream is detected, or an exception is thrown. This method does not close the input stream.
The length of the returned array equals the number of bytes read from the stream. If len is zero, then no bytes are read and an empty byte array is returned. Otherwise, up to len bytes are read from the stream. Fewer than len bytes may be read if end of stream is encountered.
When this stream reaches end of stream, further invocations of this method will return an empty byte array.
Note that this method is intended for simple cases where it is convenient to read the specified number of bytes into a byte array. The total amount of memory allocated by this method is proportional to the number of bytes read from the stream which is bounded by len. Therefore, the method may be safely called with very large values of len provided sufficient memory is available.
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 have been read. Consequently the input stream may not be at end of stream and may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.
Return
A byte array containing the bytes read from the stream.
Parameters
The maximum number of bytes to read.