1) Create Web Page using JSP
In this example, I will explain navigation from JSP to servlet and servlet to JSP.
In this example, I will explain navigation from JSP to servlet and servlet to JSP.
form tag of Html has action attribute to navigate from JSP to servlet when we click on the Submit button.
but if we want to navigate from servlet to the JSP web page then we use response.sendRedirect() for servlet navigation.
the response is the object of HttpServletResponse class and sendRedirect() is used to0 send the complete page content to the Web browser.
Syntax of response.sendRedirect():-
response.sendRedirect("url") // direct url
response.sendRedirect("url?args="+value) #url with parameter
response.sendRedirect("url?args="+value+"&args1"+value1+"&args2"+value2) #url with multiple parameter
Step1st:- Create a JSP web page with the following code:-
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body bgcolor="cyan">
<center>
<h1>Addition Program </h1>
<form action="Addser" method="post">
<input type="text" name="txtnum1" placeholder="Enter First Number" />
<br>
<br>
<input type="text" name="txtnum2" placeholder="Enter Second Number" />
<br>
<br>
<input type="submit" name="btnsubmit" value="Click" />
</form>
</center>
Step2nd:- Create Servlet and named Addser and Write the following code:-
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class Addser
*/
@WebServlet("/Addser")
public class Addser extends HttpServlet {
private static final long serialVersionUID = 1L;
public Addser() {
super();
// TODO Auto-generated constructor stub
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//PrintWriter out = response.getWriter();
int a = Integer.parseInt(request.getParameter("txtnum1"));
int b = Integer.parseInt(request.getParameter("txtnum2"));
int c = a+b;
response.sendRedirect("additionexample.jsp?q="+c);
//out.print(c);
}
}
Step3rrd append this code on the JSP web page:-
<%
if(request.getParameter("q")!=null)
{
out.print("result is "+request.getParameter("q"));
}
%>
Another example of JSP Servlet to show data on text field:-
1) Create a JSP Web page:-
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<form action="AdditionServlet" method="post">
<h1>Addition Form</h1>
<hr>
<input type="text" name="txtnum1" placeholder="Enter First Number" value="<% if(request.getParameter("q1")!=null)
{
out.print(request.getParameter("q1"));
} %>" /><br><br>
<input type="text" name="txtnum2" placeholder="Enter Second Number" value="<% if(request.getParameter("q2")!=null)
{
out.print(request.getParameter("q2"));
} %>"/><br><br><br>
<input type="submit" name="btnsubmit" value="Click" />
<br><br>
</form>
<%
if(request.getParameter("q")!=null)
{
out.print(request.getParameter("q"));
}
%>
</body>
</html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<form action="AdditionServlet" method="post">
<h1>Addition Form</h1>
<hr>
<input type="text" name="txtnum1" placeholder="Enter First Number" value="<% if(request.getParameter("q1")!=null)
{
out.print(request.getParameter("q1"));
} %>" /><br><br>
<input type="text" name="txtnum2" placeholder="Enter Second Number" value="<% if(request.getParameter("q2")!=null)
{
out.print(request.getParameter("q2"));
} %>"/><br><br><br>
<input type="submit" name="btnsubmit" value="Click" />
<br><br>
</form>
<%
if(request.getParameter("q")!=null)
{
out.print(request.getParameter("q"));
}
%>
</body>
</html>
2) Create Servlet and named it AdditionServlet:-
import java.io.IOException;
import java.io.PrintStream;
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 AdditionServlet extends HttpServlet {
protected void doPostt(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
PrintWriter out = response.getWriter();
int num1 = Integer.parseInt(request.getParameter("txtnum1"));
int num2 = Integer.parseInt(request.getParameter("txtnum2"));
int num3 = num1+num2;
// out.write("result is "+num3);
response.sendRedirect("index.jsp?q="+num3+"&q1="+num1+"&q2="+num2);
}
}
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