Spring MVC and JQuery for Ajax Form Validation

In this tutorial, we will see how to validate a form on server side using Ajax with Spring MVC and JQuery. Spring MVC provides a very convenient process for adoption of Ajax with annotation driven configuration. We will use this annotation driven configuration to send Ajax response in form of JSON data. The response will contain state of the form validation and error messages in any error exist in form data.

Tools Used:

Spring MVC 3.0.3
JQuery 1.4.2
Jackson 1.5.3

In the example, we will add users with name and education to a list using Ajax and Spring MVC. The user data will be send to Spring MVC controller with the help of JQuery and the controller will return the full list of users added till time if there is no validation error in form data or the controller will return validation errors if they present in form data.

So, we will learn two important things in this tutorial:

How to validate form data using Ajax in Spring MVC with the help of JQuery?
and how send back list of objects to Ajax call as response ?

Domain Class for User

Following is our User domain class that will hold the form data:

package com.raistudies.domain;public class User {

    private String name = null;
    private String education = null;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getEducation() {
        return education;
    }
    public void setEducation(String education) {
        this.education = education;
    }
 }

There are two fields in our User domain object name and education.
Ajax response domain class for sending JSON response
Following is the domain object that will we use to send response:

package com.raistudies.domain;

public class JsonResponse {
        private String status = null;
        private Object result = null;
        public String getStatus() {
                return status;
        }
        public void setStatus(String status) {
                this.status = status;
        }
        public Object getResult() {
                return result;
        }
        public void setResult(Object result) {
                this.result = result;
        }

}

It contain two properties, “status” and “result”. “status” field is of type String and will contain “FAIL” or “SUCCESS”. “result” will contain the other data that are to be send back to the browser.
UserController.java

package com.raistudies.controllers;

import java.util.ArrayList;
import java.util.List;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.validation.BindingResult;
import org.springframework.validation.ValidationUtils;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import com.raistudies.domain.JsonResponse;
import com.raistudies.domain.User;

@Controller
public class UserController {
        private List<User> userList = new ArrayList<User>();

        @RequestMapping(value="/AddUser.htm",method=RequestMethod.GET)
        public String showForm(){
                return "AddUser";
        }

        @RequestMapping(value="/AddUser.htm",method=RequestMethod.POST)
        public @ResponseBody JsonResponse addUser(@ModelAttribute(value="user") User user, BindingResult result ){
                JsonResponse res = new JsonResponse();
                ValidationUtils.rejectIfEmpty(result, "name", "Name can not be empty.");
                ValidationUtils.rejectIfEmpty(result, "education", "Educatioan not be empty");
                if(!result.hasErrors()){
                        userList.add(user);
                        res.setStatus("SUCCESS");
                        res.setResult(userList);
                }else{
                        res.setStatus("FAIL");
                        res.setResult(result.getAllErrors());
                }

                return res;
        }

}

showForm() is used to shoe the Add user form to browser. method addUser() is will handle the ajax request and validate the User object and if there is no validation error in form data it will set the userList object to result property of JsonResponse class with status as “SUCCESS“. But, if there are errors in form data it will extract list of errors from BindingResult object using getAllErrors() method and set to result property of JsonResponse class with status as “FAIL“.

AddUser.jsp

Following is the jsp page that calls the UserController using Ajax with the help of JQuery:

<%@ 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>Add Users using ajax</title>
<script src="<%=request.getContextPath() %>/js/jquery.js"></script>
<script type="text/javascript">
        var contexPath = "<%=request.getContextPath() %>";
</script>
<script src="<%=request.getContextPath() %>/js/user.js"></script>
<link rel="stylesheet" type="text/css" href="<%=request.getContextPath() %>/style/app.css">
</head>
<body>
<h1>Add Users using Ajax ........</h1>
        <table>
                <tr><td colspan="2"><div id="error" class="error"></div></td></tr>
                <tr><td>Enter your name : </td><td> <input type="text" id="name"><br/></td></tr>
                <tr><td>Education : </td><td> <input type="text" id="education"><br/></td></tr>
                <tr><td colspan="2"><input type="button" value="Add Users" onclick="doAjaxPost()"><br/></td></tr>
                <tr><td colspan="2"><div id="info" class="success"></div></td></tr>
        </table>
</body>
</html>

The jsp page includes a js file user.js that has been used for holding the definition of the JavaScript method doAjaxPost() which produces the ajax class and also use the response of the Ajax call to dynamically update the page data.
user.js
Following is the code for ajax class and interpreting the response received from Spring MVC controller:

function doAjaxPost() {
    // get the form values
    var name = $('#name').val();
    var education = $('#education').val();

    $.ajax({
        type: "POST",
        url: contexPath + "/AddUser.htm",
        data: "name=" + name + "&education=" + education,
        success: function(response){
            // we have the response
            if(response.status == "SUCCESS"){
                userInfo = "<ol>";
                for(i =0 ; i < response.result.length ; i++){
                    userInfo += "<br><li><b>Name</b> : " + response.result[i].name +
                    ";<b> Education</b> : " + response.result[i].education;
                 }
                 userInfo += "</ol>";
                 $('#info').html("User has been added to the list successfully. " + userInfo);
                 $('#name').val('');
                 $('#education').val('');
                 $('#error').hide('slow');
                 $('#info').show('slow');
             }else{
                 errorInfo = "";
                 for(i =0 ; i < response.result.length ; i++){
                     errorInfo += "<br>" + (i + 1) +". " + response.result[i].code;
                 }
                 $('#error').html("Please correct following errors: " + errorInfo);
                 $('#info').hide('slow');
                 $('#error').show('slow');
             }
         },
         error: function(e){
             alert('Error: ' + e);
         }
    });
}

$.ajax() method of JQuery has been used for making an Ajax call here which sends the form data name and education field values to Spring Controller. On success of the Ajax call, it first checks the status field of the response. Note that, the response object here is the JSON representation of the JsonResponse java object.
If the status field of the response is “SUCCESS” then it iterates through the user list using the notation response.result[i] , note that the list object of java is converted to json array by Jackson library.
If the status is “FAIL” the the result object will contain the validation errors which we can access using the notation response.result[i].code , here the code will return error message added in Spring controller.
While running the example in tomcat 6 server, it will open following form :

Ajax Validation Form

Just click on the “Add Users” button without entering any value, it will show errors for the field as shown in the bellow image:

Ajax Validation Show Error in Page

Now enter any name and education and click on the “Add Users” button. It will add the user detail to list and also show the info of the whole user list on the page :