Problem to call servlet from Java class

[fai fai]

Dear expert:

I had created a simple java class to call a simple servlet without any error however the servlet do not have any display(suppose my servlet will display output to Tomcat console for every invokement). Could anyone could explain this issue ???

Following is my JAVA class

JAVA Class

 
package myClass;
import java.awt.*;
import java.net.*;
import java.io.*;
import java.util.*;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.ExecutionException;

class testurl {
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        testurl task = new testurl();
		task.yyxx();
   }

    public void yyxx() {
    try {
		URL aURL = new URL("http://localhost:8080/CMSA_Proj/myClass.NewServlet");
		URLConnection aConnection = aURL.openConnection();
		aConnection.setDoInput(true);
		aConnection.setDoOutput(true);
		aConnection.setUseCaches(false);
		aConnection.setDefaultUseCaches(false);
		aConnection.setRequestProperty("Content-Type","application/octet-stream");
		aConnection.connect();
	} catch (Exception e) { System.out.println(e); }
	}
}

For Servlet side, I had configure the web.xml with follow
- <servlet-mapping>
<servlet-name>NewServlet</servlet-name>
<url-pattern>/myClass.NewServlet</url-pattern>
</servlet-mapping>

Servlet code:

 
package myClass;

import java.sql.*;
import java.util.*;
import java.io.*;
import javax.servlet.http.*;
import javax.servlet.*;

public class NewServlet extends HttpServlet {
   
    public void init(ServletConfig config) throws ServletException
	{
                System.out.println("PassServlet ===> entered");
                super.init();
	}

    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            System.out.println("NewServlet ==> processRequest");
        } finally { 
            out.close();
        }
    } 

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
        System.out.println("NewServlet ==> doGet");
    } 

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
        System.out.println("NewServlet ==> doPost");
    }

    public String getServletInfo() { return "Short description"; }

    public void service(HttpServletRequest request,HttpServletResponse response) throws
    ServletException, IOException  {
     try {
        System.out.println("NewServlet ==> services");
     } catch(Exception e) {System.out.println(e);}
    }
}

[Matthew Brown]

I may be missing something, but...

1. Your servlet doesn't appear to be producing any content - you don't write anything to the PrintWriter.

2. Even if it did, your class reading the servlet doesn't appear to read the content - you need to get hold of the InputStream from the URLConnection and read from it.

[fai fai]

Thanks Matthew Brown,

The reason why I don't code any read/write action in servlet because I just want to test the connection from JAVA main class to servlet class.

[Hebert Coelho]

And, now it's working?

[vijin das]

what about httpclient ?.... link

[Michael Angstadt]

In the deployment descriptor, you must also include a <servlet> tag, which allows you to specify the fully-qualified class name of the servlet. You have only posted the <servlet-mapping> tag in your forum post.

In order to actually send the HTTP request using the URLConnection class, I think that you have to call getInputStream(). This will send the request and allow you to access the body of the response.

Also, I see that you are setting the request's content type...since you are not putting anything in the request body, you do not need to do this. The servlet will still accept your request just fine.

In addition, you should not be overriding init(ServletConfig). The method you should override is init().