RequestDispatcherInterface Concept in Servlet
1.forward()
2.include()
================================================================================
//index.html
//FirstServlet.java
//SecondServlet.java
//ThirdServlet.java
//web.xml
================================================================================
//index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<h1><center>RequestDispatcher Example</center></h1>
<body bgcolor="#E6E6FA" >
<form action="FirstServlet">
<table border="2" align="center">
<tr><td>Employee Name</td><td><input type="text" name="ename"></td></tr>
<tr><td>Employee Password</td><td><input type="password" name="epass"></td></tr>
<tr><td>Employee Address</td><td><input type="text" name="address"></td></tr>
<tr><td>Employee Email </td><td><input type="email" name="email"></td></tr>
<tr><td>Employee Salary</td><td><input type="text" name="esal"></td></tr>
<tr><td><input type="submit" value="submit"></td>
</table>
</form>
</body>
</html>
===============================================================================
//FirstServlet.java
package govind;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
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;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
String ename = request.getParameter("ename");
String epass=request.getParameter("epass");
String eadd = request.getParameter("address");
String email=request.getParameter("email");
String esalry=request.getParameter("esal");
out.println("FirstServlet Result:");
out.println("Employee Name=:"+ename);
out.println("Employee Password=:"+epass);
out.println("Employee Address=:"+eadd);
out.println("Employee Email=:"+email);
out.println("Employee Salary=:"+esalry);
RequestDispatcher rd=null;
//ServletContext context =null;
// Ist way :-getting RequestDispatcher by ServletRequest
if(ename.equalsIgnoreCase("govind")&&epass.equalsIgnoreCase("khan"))
{
rd = request.getRequestDispatcher("/SecondServlet");
rd.forward(request, response);
}
else
{
rd = request.getRequestDispatcher("ThirdServlet");
rd.include(request, response);
}
// 2nd way :-getting RequestDispatcher by ServletContext
/*if(ename.equalsIgnoreCase("govind")&&epass.equalsIgnoreCase("khan"))
{
context = getServletContext();
rd=context.getRequestDispatcher("/SecondServlet");
rd.forward(request, response);
}
else
{
context = getServletContext();
rd=context.getRequestDispatcher("/ThirdServlet");
//rd=context.getNamedDispatcher("ThirdServlet");
rd.include(request, response);
}
*/
}
}
===============================================================================
//SecondServlet.java
package govind;
import java.io.IOException;
import java.io.PrintWriter;
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;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
String ename = request.getParameter("ename");
String epass=request.getParameter("epass");
String eadd = request.getParameter("address");
String email=request.getParameter("email");
String esalry=request.getParameter("esal");
out.println("SecondServlet Result:");
out.println("Employee Name=:"+ename);
out.println("Employee Password=:"+epass);
out.println("Employee Address=:"+eadd);
out.println("Employee Email=:"+email);
out.println("Employee Salary=:"+esalry);
}
}
==============================================================================
//ThirdServlet.java
package govind;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ThirdServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
String ename = request.getParameter("ename");
String epass=request.getParameter("epass");
String eadd = request.getParameter("address");
String email=request.getParameter("email");
String esalry=request.getParameter("esal");
out.println("ThirdServlet Result:");
out.println("Employee Name=:"+ename);
out.println("Employee Password=:"+epass);
out.println("Employee Address=:"+eadd);
out.println("Employee Email=:"+email);
out.println("Employee Salary=:"+esalry);
}
}
=================================================================================
//web.xml
<?xml version="1.0" encoding="UTF-8"?>
<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_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>sessionmanagement</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
<servlet>
<description></description>
<display-name>FirstServlet</display-name>
<servlet-name>FirstServlet</servlet-name>
<servlet-class>govind.FirstServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>FirstServlet</servlet-name>
<url-pattern>/FirstServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>SecondServlet</display-name>
<servlet-name>SecondServlet</servlet-name>
<servlet-class>govind.SecondServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>SecondServlet</servlet-name>
<url-pattern>/SecondServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>ThirdServlet</display-name>
<servlet-name>ThirdServlet</servlet-name>
<servlet-class>govind.ThirdServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ThirdServlet</servlet-name>
<url-pattern>/ThirdServlet</url-pattern>
</servlet-mapping>
</web-app>
=============================================================================================
run 1:
if empname=govind && pass=khan
then forward method executed
o/p:-
SecondServlet Result: Employee Name=:govind Employee Password=:khan Employee Address=:madhubani Employee Email=:govindkhan@gmail.com Employee Salary=:20000
run 2:
if empname!=govind && pass=khan
then include method executed
o/p:-
FirstServlet Result: Employee Name=:ballabh Employee Password=:khan Employee Address=:madhubani Employee Email=:govindkhan@gmail.com Employee Salary=:20000
ThirdServlet Result: Employee Name=:ballabh Employee Password=:khan Employee Address=:madhubani Employee Email=:govindkhan@gmail.com Employee Salary=:20000
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