SocketRequestResponse.java - Socket Client Testing Program

SOAP Web Service Tutorials - Herong's Tutorial Examples

∟Java Socket and HttpURLConnection for SOAP

∟SocketRequestResponse.java - Socket Client Testing Program

This section provides a tutorial example on how to write a Java program using socket interface to send a request and receive a response in binary mode.

Since most Web services are based on the TCP socket communication, it is very important to have a socket level client testing program ready to troubleshoot your Web service applications.

So I wrote this simple socket program, SocketRequestResponse.java, that can be used to send a request message and receive the response message to a remote TCP based server.

/* SocketRequestResponse.java
 * Copyright (c) 2002 HerongYang.com. All Rights Reserved.
 * All rights reserved
 */
import java.io.*;
import java.net.*;
public class SocketRequestResponse {
   public static void main(String[] args) {
      PrintStream out = System.out;     

// Checking command line arguments
      if (args.length < 4) {
         out.println("Usage:");
         out.println(
            "java SocketRequestResponse host port in_file out_file");
         return;
      }
      String host = args[0];
      int port = (Integer.valueOf(args[1])).intValue();
      String inFile = args[2];
      String outFile = args[3];

      try {
// Reading the request file
         File objFile = new File(inFile);
         int reqLen = (int) objFile.length();
         byte[] reqBytes = new byte[reqLen];
         FileInputStream inStream = new FileInputStream(objFile);
         inStream.read(reqBytes);
         inStream.close();

// Sending request
         out.println("Connecting to "+host+" at "+port);
         Socket con = new Socket(host,port);
         OutputStream reqStream = con.getOutputStream();
         reqStream.write(reqBytes);
         reqStream.flush();

// Reading response
         byte[] byteBuf = new byte[1024];
         FileOutputStream outStream = new FileOutputStream(outFile);
         InputStream resStream = con.getInputStream();
         int resLen = 0;
         int len = resStream.read(byteBuf);
         while (len > -1) {
            resLen += len;
            outStream.write(byteBuf,0,len);
            out.println("Bytes received: "+len);
            len = resStream.read(byteBuf);
         }

         reqStream.close();
         resStream.close();
         outStream.close();

// Output counts
         out.println("Request length: "+reqLen);
         out.println("Response length: "+resLen);
      } catch (Exception e) {
         e.printStackTrace();
      }
   }
}

Note that:

I wrote the program using byte streams only to avoid any character encoding issues in any I/O operations.
Don't call "reqStream.close()" before finishing reading the response. It will close the entire connection.

I tested this program with several standard communication protocols like HTTP 1.0, HTTP 1.1, SOAP 1.1 and SOAP 1.2. My program worked fine in all cases. If you are interested in request and response examples of those protocols, see related Perl tutorials in this book.