Get start with Ajax, Ajax simple example with Servlet, Ajax programming with Servlet ~ balaram

Tuesday, October 9, 2012

Get start with Ajax, Ajax simple example with Servlet, Ajax programming with Servlet

I am writing here a very simple ajax program. That will take roll number from jsp page, hit serlvlet, come back with result as XML, parse in javascript and will show on jsp page.

1. ShowStudentInfo.jsp

<html><head>
<title>Binod Java Solution AJAX </title>
<script type="text/javascript">
var request; function getName(){
var roll = document.getElementById("roll").value;
var url = "http://localhost:8080/blog_demo/StudentInfo?roll="+roll;
if(window.ActiveXObject){ request = new ActiveXObject("Microsoft.XMLHTTP"); }
else if(window.XMLHttpRequest){ request = new XMLHttpRequest(); } request.onreadystatechange = showResult;
request.open("POST",url,true);
request.send();
}
function showResult(){
if(request.readyState == 4){
var response = request.responseXML;
var students = response.getElementsByTagName("Student");
var student = students[0];
document.getElementById("NamelH1").innerHTML = student.getElementsByTagName("Name")[0].text;
document.getElementById("HostelH1").innerHTML = student.getElementsByTagName("Hostel")[0].text;
document.getElementById("ContactH1").innerHTML = student.getElementsByTagName("Contact")[0].text;
}
}
</script>
</head>
<body><h2> GET STUDENT INFO </h2>
<br> Enter Roll Number <input type="text" id="roll">
<input type="button" value="Get Name" onclick="getName();"/>
<br> Name : <span id="NamelH1"></span> <br
> Hostel : <span id="HostelH1"></span> <br
> Contact : <span id="ContactH1"></span> <br>
</body>
</html>

2. Servlet java file StudentInfo.java

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class StudentInfo extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
static final long serialVersionUID = 1L;
public StudentInfo() { super(); }
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { }
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("**** STUDENT INFO ****");
String roll = request.getParameter("roll");
PrintWriter out = response.getWriter();
response.setContentType("text/xml");
System.out.println(getResult(roll)); out.println(getResult(roll));
}
public String getResult(String roll){
String name = "";
String hostel = "";
String contact = "";
if(roll.equalsIgnoreCase("110")){
name = "Binod Kumar Suman"; hostel = "Ganga"; contact = "999999999";
} else if(roll.equalsIgnoreCase("120")){
name = "Pramod Kumar Modi"; hostel = "Godawari"; contact = "111111111111";
} else{ name = "Roll Number not found"; }
String result = "<Students>";
result += "<Student>"; result += "<Name>" + name + "</Name>";
result += "<Hostel>" +hostel + "</Hostel>";
result += "<Contact>" +contact + "</Contact>";
result += "</Student>"; result += "</Students>";
return result;
}
}

Now simple run your JSP page and put the roll number like 110, it will work.
http://localhost:8080/Ajax_Demo/ShowStudentInfo.jsp

balaram

Tuesday, October 9, 2012