How to read data stream ignoring the data type in Java

Question

I am writing a client-server application in Java. The procedure is as following:

1. A client send a message of HTTP format to a registration node with

   • a request line a number of header lines
   • a blank line
   • and a body.
   • (ASCII text)

2. The registration node send a message of similar format to a server.

3. The client and server can talk (pretty like SIP).

For now, I already have created sockets of client and server, but if I want to use DataInputStream and DataOutputStream to input and output data, I also need to determine the type of data since methods like readDouble from DataInputStream.

I don't know how to do it.

Sorry if my description is a little ambiguous, Here, some sample messages that would be transferred.

REGISTER john@google.com SIPL/1.0CRLF
To: john@google.comCRLF
From: john@google.comCRLF
Call-ID: a74fbCRLF
CSeq: 0CRLF
Expires: 200CRLF
Contact: 74.125.226.161:20132CRLF
CRLF

SIPL/1.0 200 okCRLF
To: barney@google.comCRLF
From: 74.125.226.161:20300CRLF
Call-ID: 9934bcd2CRLF
CSeq: 10CRLF
Content-Length: 21CRLF
Contact: 74.125.226.161:20305CRLF
CRLF
file=foo
characters=10

Any apply will really be appreciated !!!

Answer 1

Since you are reading ASCII text, and have to deal with line breaks, you can use readers and writers, and read your data with a java.io.BufferedReader which allows you to read line by line.

BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

String line = reader.readLine();
StringBuilder buffer = new StringBuilder();
while ( line != null) {
   buffer.append(line);
   line = reader.readLine();

   // you can check here if the line is empty and decide only to read the header
   // or to split your header and body into different buffers

}
String fullText = buffer.toString();

If you send text data, you can also use something similar:

PrintWriter writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
writer.println("GET / HTTP/1.1");
writer.println("Header: value");
writer.println(); // end of header
...
writer.flush(); // if you need to flush the buffer before closing
writer.close(); // when done - flushes and closes

Place everything in a try-catch-finally block with the close() methods in the finally (or, if you use Java 7, a try-with-resources)