Saturday, 7 June 2014

Servlets : ServletRequest Attribute


Click here to watch in Youtube : https://www.youtube.com/watch?v=ss1CW19pbTo

Click the below Image to Enlarge
Servlets : ServletRequest Attribute
ServletRequestAttributeDemo Project Dir Structure
Servlets : ServletRequest Attribute

FirstServlet.java
import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

    public void init() throws ServletException
    {
        System.out.println("-----------------------------------------");
        System.out.println(" Init method is called in "
                + this.getClass().getName());
        System.out.println("--------------------------------------");
    }

    public void doGet( HttpServletRequest request, HttpServletResponse response )
            throws ServletException, IOException
    {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        request.setAttribute("CompanyName", "Wipro");
        request.setAttribute("Location", "India");

        System.out.println("Firstservlet will forward the request to SecondServlet soon");

        try
        {
            Thread.sleep(10000);
        }
        catch( InterruptedException e )
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        RequestDispatcher requestDispatcher = request
                .getRequestDispatcher("/servlet2");
        
        requestDispatcher.forward(request, response);

        out.close();

    }

    public void destroy()
    {
        System.out.println("-----------------------------------------");
        System.out.println(" destroy method is called in "
                + this.getClass().getName());
        System.out.println("-----------------------------------------");
    }

}

SecondServlet.java
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

    public void init() throws ServletException
    {
        System.out.println("--------------------------------------------");
        System.out.println(" Init method is called in "
                + this.getClass().getName());
        System.out.println("---------------------------------------------");
    }

    public void doGet( HttpServletRequest request, HttpServletResponse response )
            throws ServletException, IOException
    {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        String CompanyName = (String) request.getAttribute("CompanyName");
        out.print("CompanyName :  " + CompanyName + "<br>");

        out.print("*************************************************************"
                + "<br>");

        Enumeration<String> namesEnum = request.getAttributeNames();
        while( namesEnum.hasMoreElements() )
        {
            String name = (String) namesEnum.nextElement();
            out.print(name + ":");
            Object value = request.getAttribute(name);
            out.print(value);
            out.print("<br>");
        }

        out.close();
    }

    public void destroy()
    {
        System.out.println("--------------------------------------------");
        System.out.println(" destroy method is called in "
                + this.getClass().getName());
        System.out.println("--------------------------------------------");
    }

}

web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" metadata-complete="true" version="3.0">
  <display-name>ServletRequestAttributeDemo</display-name>
  <description>
        This is a simple web application with a source code organization
        based on the recommendations of the Application Developer's Guide.
    </description>
  <servlet>
    <servlet-name>s1</servlet-name>
    <servlet-class>FirstServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>s1</servlet-name>
    <url-pattern>/servlet1</url-pattern>
  </servlet-mapping>
  <servlet>
    <servlet-name>s2</servlet-name>
    <servlet-class>SecondServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>s2</servlet-name>
    <url-pattern>/servlet2</url-pattern>
  </servlet-mapping>
</web-app>

index.html
<html lang="en">
<head>
<meta charset="UTF-8">
<title>ServletContextAttributeDemo</title>
</head>
<body>
    <form action="servlet1" method="GET">
                    
        <input type="submit" value="Call FirstServlet" />
        
    </form>
</body>
</html>

Environment Used

JDK version :1.7.0_51
Tomcat version : 7.0.50 

To Download ServletRequestAttributeDemoApp Project Click the below link

https://sites.google.com/site/javaee4321/servlets/ServletRequestAttributeDemoApp.zip?attredirects=0&d=1

See also:

  • Servlets Tutorial
  • All Design Patterns Links
  • No comments:

    Post a Comment

    Google+ Followers

    Google+ Badge