Java ajax passing values from jsp to servlet

java jquery ajax jsp servlets

27,597

Solution 1

in main.js type is type: 'post' and you have written code in get method do type:'get'

Solution 2

there is no name attribute in your input field. when you are doing

String val = request.getParameter("id");

then in servlet then it will search for the input field having name="id" but in your form there is nothing so it will return null;

give name to the input field like

<input type="text" id="id" name="id"/>

also as sanjay has said your ajax has type post so change it to get as well

27,597

Author by

fscore

I am a Computer Science student.

Updated on July 09, 2022

Comments

fscore almost 2 years

I am trying to pass basic values such as id from jsp to the servlet through ajax. I tried everything but only null is being passed. Even console.log(val) does not print anything to browser console.

My understanding is: Web page has form values which onsubmit calls js file. js has ajax which calls the servlet and passes the data of the form. The servlet grabs data from ajax by request.getParameter(val)

Here is my code:

Main.jsp

<%@ 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>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js" type="text/javascript">
<script src="js/main.js" type="text/javascript"></script>
</head>
<body>

<form method="post" action="Main" id="firstform">
    <h1>Enter name:</h1>
    <input type="text" name="id" id="id" />
    <input type="submit" name="submit"/>
</form>

</body>
</html>

main.js

var form = $('#firstform');
console.log("gi");
form.submit(function()
{
    $.ajax({
        url: 'Main',
        data: form.serialize(),
        type: 'post',
        success: function(data){ 
            console.log(data);
        }
            });

    //return false;

});

Main.java

package servlets;

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 Main
 */
@WebServlet("/Main")
public class Main extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Main() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        int ids;
        response.setContentType("text/html;charset=UTF-8");

        PrintWriter out = response.getWriter();
        String val = request.getParameter("id");
        System.out.print(val);
        if(val != null){
            ids = Integer.parseInt(val);
            out.print(ids); //
        }

    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

**Problems:
1)values passed from jsp to servlet
2)console.log doesnt print anything on browser console

1) works but 2) still doesnt.**

fscore almost 10 years

I changed to 'post' now but still no result. It doesnt even print on java console as mentioned here - System.out.print(val);
fscore almost 10 years

So type should be 'get' and not post... it worked then :) thanks
fscore almost 10 years

I accepted your answer although.. console.log doesnt still work
SpringLearner almost 10 years

@fscore first try by submiting the form without using ajax and let me know if you get any values or not
SpringLearner almost 10 years

@fscore you mean this line console.log("gi");
fscore almost 10 years

yes it does not print. infact even if I do console.log(id) it doesnt print that too
SpringLearner almost 10 years

@fscore if not errors then you should atleast get this in console console.log("gi");.atleast gi will get printed