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Ajitesh is passionate about various different technologies including programming languages such as Java/JEE, Javascript, PHP, .NET, C/C++, SCALA, mobile programming languages etc and, computing fundamentals such as application security, cloud computing, API, mobile apps, google glass, big data etc. Currently, he is exploring different Javascript frameworks including AngularJS and the likes. He is also focusing on Big Data, especially, data science aspect of Big Data. He is working as a Principal Architect with Evoke technologies based out of Hyderabad, India. Ajitesh is a DZone MVB and is not an employee of DZone and has posted 49 posts at DZone. You can read more from them at their website. View Full User Profile

AngularJS – Single Page App with RESTful APIs & Spring MVC

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The article presents recipe to create single page application with AngularJS & Spring MVC where different pages are required to do transactions with server using RESTful API. The demonstration is created on this page, http://hello-angularjs.appspot.com/angularjs-single-page-app-restful-apis.

Code samples and related concepts are presented for following requirements of single page app:

  • Initially one page is loaded with side navigation.
  • Clicking on side navigation loads new view (data) from server by consuming RESTful API using ngResource, $resource service with “query” action method
  • Clicking on individual items link loads the related data from server, again by consuming RESTful API using ngResource, $resource service with “get” action method
  • Submitting a set of data consumes a RESTful API and sends the data to the server for persistence. Here, $resource service with “save” action method is used.

The demo app presents a trivial app which allow users to do some of the following:

  • Create new users
  • Get all users
  • Get users by Id

In this example, one userservice is created that does the RESTful transaction. This userservice is used in multiple different controllers used to load/manage different views.

Following are keys to creating AngularJS Single Page App that consumes RESTful APIs:

  • Angular module dependencies
  • Routing code that defines routes for different links. 
  • Code to manage the transactions with RESTful APIs. I created a custom User service that provides APIs to do transactions with RESTful APIs
  • Controller code that defines how data will be retrieved/handled in each view
  • Server side code to receive RESTful API request and send appropriate response
Angular Module Dependencies

Following are two different modules that will be required to be included when creating app:

  • ngRoute
  • ngResource

Following is the code sample:

var userApp = angular.module("userApp", [ 'ngRoute', 'ngResource' ]);

You would also have to include following withinelement:

<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.18/angular-route.js"></script>
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.18/angular-resource.js"></script>
Routing Code

Following represents the routing code which defines how each link/path will be processed (controller, templateURL)

userApp.config(function($routeProvider) {
	$routeProvider.when('/users/new', {
		controller : 'NewUserCtrl',
		templateUrl : 'views/newuser.html'
	}).when('/users/:userId', {
		controller : 'UsersByIdCtrl',
		templateUrl : 'views/userbyid.html'	
	}).when('/users', {
		controller : 'UsersCtrl',
		templateUrl : 'views/users.html'	
		controller : 'SpaCtrl',
		templateUrl: 'views/spahome.html'
User Service – Transactions with RESTful APIs

Following code is used to userservice using AngularJS factory recipe. This userservice internally instantiates User class by passing $resource service to its constructor function. Note that $scope is passed to individual APIs/methods and that the value for model is set within each API. Once updated, the model values appear on the UI.

userApp.factory( 'userservice', [ '$resource', function( $resource ){
	return new User( $resource );
}] );
function User( resource ) {
	this.resource = resource; 
	this.createUser = function ( user, scope ) {
		// Save Action Method
		var User = resource('/users/new');		
		User.save(user, function(response){
			scope.message = response.message;
	this.getUser = function ( id, scope ) {
		// GET Action Method
		var User = resource('/users/:userId', {userId:'@userId'});
		User.get( {userId:id}, function(user){
			scope.user = user;
	this.getUsers = function( scope ) {
		// Query Action Method
		var Users = resource('/users/all');
			scope.users = users;
AngularJS Controller Code for Different Views
// Controller when the main page/view loads
userApp.controller("SpaCtrl", [ '$scope', function($scope) {			
} ]);
// Controller for All Users View
userApp.controller("UsersCtrl", [ '$scope','userservice', function($scope, userservice) {	
	userservice.getUsers( $scope );		
} ]);
// Controller for New User View
userApp.controller("NewUserCtrl", [ '$scope','userservice', function($scope, userservice) {				
	userservice.getUsers( $scope );	
	$scope.createNewUser = function(){
		var newuser = { 'firstname':$scope.firstname, 'lastname': $scope.lastname, 'address':$scope.address, 'email':$scope.email };
		// Call UserService to create a new user
		userservice.createUser ( newuser, $scope );
		// Push new user to existing table column
		$scope.users.push( newuser );
		// Reset fields values
} ]);
// Controller for Individual User View
userApp.controller("UsersByIdCtrl", [ '$scope','userservice', '$routeParams', function($scope, userservice, $routeParams) {	
	userservice.getUser($routeParams.userId, $scope);	
} ]);
Spring MVC Controller Code for RESTful API

Following demonstrates the Spring MVC Controller code for three different RESTful APIs with URL written as part of RequestMapping value parameter:

All Users (/users/all)
@RequestMapping(value = "/users/all", method = RequestMethod.GET)
        public  @ResponseBody String getAllUsers( ModelMap model ) {
            String jsonData = "[{\"id\":\"3253123\",\"firstname\":\"Chris\",\"lastname\":\"Johnson\",\"address\":\"211, Geoffrey Drive\",\"city\":\"Newark\",\"phone\":\"999-888-6666\",\"email\":\"chrisj@yahoo.com\"},{\"id\":\"67643837\",\"firstname\":\"Bill\",\"lastname\":\"Derkson\",\"address\":\"201, Sleepy Hollow Drive\",\"city\":\"Newark\",\"phone\":\"999-777-2222\",\"email\":\"billd@gmail.com\"}]";
            return jsonData;

New Users (/users/new)

@RequestMapping(value = "/users/new", method = RequestMethod.POST)    
        public  @ResponseBody String createNewUser( @RequestBody User user )   {        
            // Code processing the input parameters
             String response = "{\"message\":\"Created New User - firstname: " + user.getFirstname() + ", lastname: " + user.getLastname() + ", address: " + user.getAddress() + ", email: " + user.getEmail()+"\"}";
            return response;

User By Id (/users/{id}

@RequestMapping(value = "/users/{id}", method = RequestMethod.GET)    
        public  @ResponseBody String getUsersById( @PathVariable("id") long userId )   {        
            // Code processing the input parameters
            String response = "{\"id\":\""+ userId + "\",\"firstname\":\"FirstName\",\"lastname\":\"LastName\",\"address\":\"Some Address\",\"age\":\"SomeNo\",\"email\":\"sometext@gmail.com\"}";
            return response;

After having found the recipe for creating single page app that could consume RESTful APIs, I am not sure if I would be using any other way to create single page app other than the way described in this article. Please feel free to share your ideas/suggestions/thoughts.

Published at DZone with permission of Ajitesh Kumar, author and DZone MVB. (source)

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)