Tuesday, September 17, 2013

How to load URL Connection to Client machine using Java servlet

This example explains how to load web result to client browser.Web result mean output of some third party application(Ex:image, bill, any URL..etc).

Implementation steps;
First Create URL object and create HttpURLConnection by using above object.openConnection();Then create BufferedInputStream by passing InputStream to constructer of BufferedInputStream.Finally writes this buffered input stream data to output stream of the servlet.

package com.srccodes.example;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;



public class OldBillClient extends HttpServlet {
    private static final long serialVersionUID = 1L;


    public OldBillClient() {
        super();
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
        //System.out.println("Done");
    }

    HttpURLConnection conn;

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
       
        doDL();//Create URL connection for download and show
       
        BufferedInputStream in = new BufferedInputStream(conn.getInputStream());//Used created connection
        OutputStream sos = response.getOutputStream();
        try {
            int i = 0;
            while ((i = in.read()) != -1) {
                sos.write(i);//Writes data to out put stream
                //System.out.write(i);
            }
            in.close();
            sos.flush();
        } finally {
            if (in != null)
                in.close();
            if (sos != null) {
                sos.flush();
                sos.close();
            }
        }
    }
   
    /**
     * set URL connection
     */
    private void doDL() {
        try {
            URL obj = new URL("https://www.google.lk/#q=Test");//Ex : http://170.26.29.180/com/test/?para_1=value_1&para_2=value_2
            conn = (HttpURLConnection) obj.openConnection();
            conn.setReadTimeout(5000);
        } catch (java.io.IOException ioE) {
            ioE.getMessage();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

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