How to use Inputstream.available () in Java Network programming __ algorithm

If the byte stream from the server does not make any mark, only after the data is sent flush (), then the client can use Inputstream.available () to determine the length of the stream, but must be called read () at least once, otherwise you can only get 0 value.

The instance code is as follows:

Get a InputStream from a Blob object
InputStream input = Imageblob.getbinarystream ();

Servletoutputstream is used to transmit data,
OutputStream out = Response.getoutputstream ();

int firstchar = Input.read ();
int length = input.available ();

Convert it to binary data
byte [] image = new byte [length];
image[0] = (byte) Firstchar;

int len = 0;
while (len = Input.read (image, 1, length-1))!=-1) ... {
Out.write (image, 0, Len);
}
Out.flush ();
Out.close ();