AngularJS provides the following features which makes developing web apps easy:
1. Two way data binding
2. Dependency Injection
3. Custom HTML Directives
4. Easy integration with REST webservices using $http, $resource, Restangular etc
5. Support for Testing
and many more...
Though there are lot more features than the above mentioned list, these are the very commonly used features.
I am not going to explain what 2-way data binding is, how $scope works here because there are tons of material already on web.
As a Java developer, I will be using SpringBoot based RESTful back-end services. If you want you can use JavaEE/JAX-RS to build REST back-end services. Also you might like using NetBeans as it has wonderful AngularJS auto-completion support out of the box.
So lets get start coding AngularJS HelloWorld application.
Create index.html with the following content and start your server and point your browser to http://localhost:8080/hello-angularjs/index.html
<html> <head> <title>Hello AngularJS</title> <meta charset="UTF-8"> <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script> </head> <body ng-app> <p>Enter Name: <input type="text" ng-model="myname"> </p> <p>Hello {{myname}}!!</p> </body> </html> - See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
Now start typing in input text and your Hello {{myname}} would immediately reflect the value you are entering in input text field.
Ok, we are done with "HelloWorld" ceremony and warm up :-).
We have used AngularJS CDN URL for loading AngularJS library. We can download AngularJS from https://angularjs.org/ add the angular.min.js script.
But we will be using WebJars (http://www.webjars.org/) which provides the popular javascript libraries as maven jar modules along with transitive dependencies. If we want to use Twitter Bootstrap we should include jQuery also. But using WebJars I need to configure only bootstrap jar dependency and it will pull jquery dependency for me.
Let us create a SpringBoot project by selecting File -> New -> Spring Starter Project, select "Web" and "Data JPA" modules and Finish.
If you are not using STS then you can create this starter template from http://start.spring.io/ and download it as zip.
We will be using Bootstrap and font-awesome javascript libraries to build our Web UI.
Lets configure H2 database, AngularJS, Bootstrap and font-awesome libraries as WebJar maven dependencies in pom.xml.
As it is a SpringBoot jar type application we will put all our html pages in src/main/resources/public folder and all our javascripts, css, images in src/main/resources/static folder.
- Now modify the AngularJS CDN reference to <script src="webjars/angularjs/1.2.19/angular.js"></script>.
- Lets include the bootstrap and font-awesome css/js in our index.html. Also we will be using angular-route module for page navigation and hence we need to include angular-route.js as well.
- Lets create app.js file which contains our main angularjs module configuration in src/main/resources/static/js folder.
- Also create controllers.js, services.js, filters.js, directives.js in the same folder and include them in index.html.
<!doctype html> <html> <head> <meta charset="utf-8"/> <title>DashBoard</title> <link rel="stylesheet" href="webjars/bootstrap/3.2.0/css/bootstrap.css"/> <link rel="stylesheet" href="webjars/font-awesome/4.1.0/css/font-awesome.css"/> <link rel="stylesheet" href="css/styles.css"/> </head> <body ng-app> <p>Enter Name: <input type="text" ng-model="myname"> </p> <p>Hello {{myname}}!!</p> <script src="webjars/jquery/1.11.1/jquery.js"></script> <script src="webjars/bootstrap/3.2.0/js/bootstrap.js"></script> <script src="webjars/angularjs/1.2.19/angular.js"></script> <script src="webjars/angularjs/1.2.19/angular-route.js"></script> <script src="js/app.js"></script> <script src="js/controllers.js"></script> <script src="js/services.js"></script> </body> </html> - See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
In Application.java file add the following RequestMapping to map context root to index.html.
package com.sivalabs.app;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
@Controller
class HomeController
{
@RequestMapping("/")
public String home() {
return "index.html";
}
}
- See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
view raw
HelloAngular-Application.java hosted with ❤ by
GitHub
Now run this Application.java as stand-alone class and go to http://localhost:8080/. It should work same as earlier.
Now we have basic setup ready. Lets build a very simple Todo application.
Create a JPA entity Todo.java, its Spring Data JPA repository interface and TodoController to perform Read/Create/Delete operations.
package com.sivalabs.app.entities;
@Entity
public class Todo {
@Id @GeneratedValue(strategy=GenerationType.AUTO)
private Integer id;
private String description;
@Temporal(TemporalType.TIMESTAMP)
private Date createdOn = new Date();
//setters and getters
}
package com.sivalabs.app.repos;
public interface TodoRepository extends JpaRepository<Todo, Integer>{
}
package com.sivalabs.app.controllers;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import com.sivalabs.app.entities.Todo;
import com.sivalabs.app.repos.TodoRepository;
@RestController
@RequestMapping("/todos")
public class TodoController {
@Autowired
private TodoRepository todoRepository;
@RequestMapping(value="", method=RequestMethod.GET)
public List<Todo> persons() {
return todoRepository.findAll();
}
@RequestMapping(value="", method=RequestMethod.POST)
public Todo create(@RequestBody Todo todo) {
return todoRepository.save(todo);
}
@RequestMapping(value="/{id}", method=RequestMethod.DELETE)
public void delete(@PathVariable("id") Integer id) {
todoRepository.delete(id);
}
}
- See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
Create DatabasePopulator to setup some initial data.
package com.sivalabs.app;
import java.util.Arrays;
import java.util.Date;
import javax.annotation.PostConstruct;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import com.sivalabs.app.entities.Todo;
import com.sivalabs.app.repos.TodoRepository;
@Component
public class DatabasePopulator
{
@Autowired
private TodoRepository todoRepository;
@PostConstruct
void init()
{
try {
Todo t1 = new Todo(null, "Task 1", new Date());
Todo t2 = new Todo(null, "Task 2", new Date());
Todo t3 = new Todo(null, "Task 3", new Date());
this.todoRepository.save(Arrays.asList(t1,t2,t3));
} catch (Exception e) {
e.printStackTrace();
}
}
}
- See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
Now our back-end RESTful web services ready at the following URLs.
GET - http://localhost:8080/todos for getting list of Todos
POST - http://localhost:8080/todos for creating new Todo
DELETE - http://localhost:8080/todos/1 to delete Todo(id:1)
Lets create our main angularjs module 'myApp' and configure our application routes in app.js file.
var myApp = angular.module('myApp',['ngRoute']);
myApp.config(['$routeProvider','$locationProvider',
function($routeProvider, $locationProvider) {
$routeProvider
.when('/home', {
templateUrl: 'templates/home.html',
controller: 'TodoController'
})
.otherwise({
redirectTo: 'home'
});
}]);
- See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
Now update index.html to hookup myApp module at the root of page using and use to load the current route template.
<!doctype html> <html ng-app="myApp"> <head> <meta charset="utf-8"/> <title>DashBoard</title> <link rel="stylesheet" href="webjars/bootstrap/3.2.0/css/bootstrap.css"/> <link rel="stylesheet" href="webjars/font-awesome/4.1.0/css/font-awesome.css"/> <link rel="stylesheet" href="css/styles.css"/> </head> <body> <div class="container"> <div ng-view></div> </div> <script src="webjars/jquery/1.11.1/jquery.js"></script> <script src="webjars/bootstrap/3.2.0/js/bootstrap.js"></script> <script src="webjars/angularjs/1.2.19/angular.js"></script> <script src="webjars/angularjs/1.2.19/angular-route.js"></script> <script src="js/app.js"></script> <script src="js/controllers.js"></script> <script src="js/services.js"></script> </body> </html> - See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
Create home.html template in src/main/resources/public/templates folder.
<div class="col-md-8 col-md-offset-2"> <form class="form-horizontal" role="form"> <div class="form-group form-group-md"> <div class="col-md-10"> <input type="text" class="form-control" ng-model="newTodo.description"> </div> <button class="btn btn-primary" ng-click="addTodo(newTodo)">Add</button> </div> </form> <table class="table table-striped table-bordered table-hover"> <thead> <tr> <th width="70%">Item</th> <th>Date</th> <th>Delete</th> </tr> </thead> <tbody> <tr ng-repeat="todo in todos"> <td>{{todo.description}}</td> <td>{{todo.createdOn | date}}</td> <td><button class="btn btn-danger" ng-click="deleteTodo(todo)">Delete</button></td> </tr> </tbody> </table> <br/> </div> - See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
It is a very simple html page with some bootstrap styles and we are using some angularjs features.
We are using ng-repeat directive to iterate through array of Todo JSON objects, ng-click directive to bind a callback function to button click.
To invoke REST services we will use angularjs built-in $http service. $http service resides in angular-route.js, don't forget to include it in index.html.
$http.verb('URI')
.success(success_callback_function(data, status, headers, config){
//use data
})
.error(error_callback_function(data, status, headers, config) {
alert('Error loading data');
});
For example: to make GET /todos REST call
$http.get('todos')
.success(function(data, status, headers, config) {
//use data
})
.error(function(data, status, headers, config) {
alert('Error loading data');
});
Create TodoController in controllers.js file. In TodoController we will create functions to load/create/delete Todos.
angular.module('myApp')
.controller('TodoController', [ '$scope', '$http', function ($scope, $http) {
$scope.newTodo = {};
$scope.loadTodos = function(){
$http.get('todos')
.success(function(data, status, headers, config) {
$scope.todos = data;
})
.error(function(data, status, headers, config) {
alert('Error loading Todos');
});
};
$scope.addTodo = function(){
$http.post('todos',$scope.newTodo)
.success(function(data, status, headers, config) {
$scope.newTodo = {};
$scope.loadTodos();
})
.error(function(data, status, headers, config) {
alert('Error saving Todo');
});
};
$scope.deleteTodo = function(todo){
$http.delete('todos/'+todo.id)
.success(function(data, status, headers, config) {
$scope.loadTodos();
})
.error(function(data, status, headers, config) {
alert('Error deleting Todo');
});
};
$scope.loadTodos();
}]);
- See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
Now point your browser to http://localhost:8080/. You should see list of Todos and New Todo Entry form and Delete option for each Todo item.
By now we get some hands-on with AngularJS basic features.
In next post I will explain using multiple routes, multiple controllers and services. Stay tuned :-) - See more at: http://www.sivalabs.in/2014/09/angularjs-tutorial-getting-started-with.html#sthash.q8epstbb.dpuf
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