AngularJS Interacting with Java Servlet using JSON
In this post, I am going to demonstrate a simple example on how to make AJAX calls from a JSP page to a Servlet using AngularJS and update the same JSP page back with the JSON response from the Servlet. In other words, this post will give you an overview on how to integrate AngularJS in a Java web applications.
There are many JSON libraries available that can be used to pass AJAX updates between the server and the client. I am going to use google’s gson library in this example.
Below are the steps to reproduce to create a simple AngularJS enabled Java Web Application using Eclipse and Tomcat 7,
How to use?
First of all create a “Dynamic Web Project” in Eclipse and download the AngularJS library and place in js folder of eclipse work-space, and refer this files in the head section in the jsp, this file is responsible for the AJAX call made to the servlet and for updating the response back in the JSP.
Jsp Page
AJAX with Servlets using AngularJS First Name : {{person.firstName}}
Last Name : {{person.lastName}}
HTML – Data Binding
We can display JSON data values in jsp by using their attributes in expressions like {{person.firstName}}, {{person.lastName}} etc.. Here the id=”ng-app” is most important for Internet Explorer browser data binding.
ng-controller
Specifies a JavaScript controller class that evaluates HTML expressions.
ng-click
Angular on click event
Model class
package com.model; public class PersonData { private String firstName; private String lastName; public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } }
Recommended Reading:
- AJAX in Servlet & jsp using JQuery
- jQuery Tutorial for Beginners
- Autocomplete in java web application using Jquery and JSON
Servlet
Now let’s go on and write the servlet which handles this Ajax call
package com.controller; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.google.gson.Gson; import com.model.PersonData; public class AngularJsServlet extends HttpServlet { private static final long serialVersionUID = 1L; public AngularJsServlet() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PersonData personData = new PersonData(); personData.setFirstName("Mohaideen"); personData.setLastName("Jamil"); String json = new Gson().toJson(personData); response.setContentType("application/json"); response.getWriter().write(json); } }
Code Explanation
When the user clicks on “Fetch data from server” button, button click event is fired via angularJS “ng-click” directive and the ‘http’ function executes the Ajax GET request on the Servlet.
Web.xml
Make sure you have done servlet mapping in web.xml as shown below
index.jsp javaAngularJS com.controller.AngularJsServlet javaAngularJS /javaAngularJS
Demo
Once you done with above steps then Right click on project –> Run As –> Run on Server
(Note: I have used tomcat server to run this application. If you are not sure how to configure tomcat server in eclipse please follow this link).
Click button: Fetch data from server to pass HTTP request using angularJS where Java servlet will return data as below:
AngularJS demo
Hi,
I have problem in this code, when i take data from responce it give me whole content of specified page. i want only JSON. please help me.
Thanks,
Harshad
Rather than writing Success and Error function after ‘ $http({
method : ‘GET’,
url : ‘javaAngularJS’
}). ‘
You can go with ” .then(function(response){
$scope.person = response.data;
}); “
what about catching any error encountered while running servlet in angularjs ???
Nice Example.
Very good article. it is very useful for me thank u
am not sure what went wrong with syntax at script , i modified it to separate mainaapp, and controller worked fine . If not i can see data binding coursers with attributes ….
AJAX with Servlets using AngularJS
Fetch data from server
First Name : {{person.firstName}}
Last Name : {{person.lastName}}
//myapp.js
var myApp = angular.module(‘myApp’, []);
//mycontroller.js
myApp.controller(‘MyController’,function($scope, $http) {
$scope.getDataFromServer = function() {
$http({
method : ‘GET’,
url : ‘javaAngularJS’
}).success(function(data, status, headers, config) {
$scope.person = data;
}).error(function(data, status, headers, config) {
// called asynchronously if an error occurs
// or server returns response with an error status.
});
};
});