生活的例子

" Hello world "的例子

与工厂/服务/供应商:

var myApp = angular.module('myApp', []);
 
//service style, probably the simplest one
myApp.service('helloWorldFromService', function() {
    this.sayHello = function() {
        return "Hello, World!"
    };
});
 
//factory style, more involved but more sophisticated
myApp.factory('helloWorldFromFactory', function() {
    return {
        sayHello: function() {
            return "Hello, World!"
        }
    };
});
    
//provider style, full blown, configurable version     
myApp.provider('helloWorld', function() {
    // In the provider function, you cannot inject any
    // service or factory. This can only be done at the
    // "$get" method.
 
    this.name = 'Default';
 
    this.$get = function() {
        var name = this.name;
        return {
            sayHello: function() {
                return "Hello, " + name + "!"
            }
        }
    };
 
    this.setName = function(name) {
        this.name = name;
    };
});
 
//hey, we can configure a provider!            
myApp.config(function(helloWorldProvider){
    helloWorldProvider.setName('World');
});
        
 
function MyCtrl($scope, helloWorld, helloWorldFromFactory, helloWorldFromService) {
    
    $scope.hellos = [
        helloWorld.sayHello(),
        helloWorldFromFactory.sayHello(),
        helloWorldFromService.sayHello()];
}​

所有angular服务都是单例:

文档(请参阅服务为单例):https://docs.angularjs.org/guide/services

最后，重要的是要认识到所有Angular服务都是应用程序单例。这意味着每个注入器只有一个给定服务的实例。

基本上，服务和工厂的区别如下:

app.service('myService', function() {

  // service is just a constructor function
  // that will be called with 'new'

  this.sayHello = function(name) {
     return "Hi " + name + "!";
  };
});

app.factory('myFactory', function() {

  // factory returns an object
  // you can run some code before

  return {
    sayHello : function(name) {
      return "Hi " + name + "!";
    }
  }
});

查看关于$ provider的演示:http://slides.wesalvaro.com/20121113/#/

这些幻灯片被用于AngularJs的一个聚会:http://blog.angularjs.org/2012/11/more-angularjs-meetup-videos.html

在AngularJS中有三种处理业务逻辑的方法:(灵感来自Yaakov的Coursera AngularJS课程):

服务 工厂 提供者

这里我们只讨论服务vs工厂

服务:

语法:

app.js

 var app = angular.module('ServiceExample',[]);
 var serviceExampleController =
              app.controller('ServiceExampleController', ServiceExampleController);
 var serviceExample = app.service('NameOfTheService', NameOfTheService);

 ServiceExampleController.$inject = ['NameOfTheService'] //very important as this protects from minification of js files

function ServiceExampleController(NameOfTheService){
     serviceExampleController = this;
     serviceExampleController.data = NameOfTheService.getSomeData();
 }

function NameOfTheService(){
     nameOfTheService = this;
     nameOfTheService.data = "Some Data";
     nameOfTheService.getSomeData = function(){
           return nameOfTheService.data;
     }     
}

index . html

<div ng-controller = "ServiceExampleController as serviceExample">
   {{serviceExample.data}}
</div>

服务的主要特点:

惰性实例化:如果服务没有被注入，它将永远不会被实例化。所以要使用它，你必须将它注入到一个模块中。 单例:如果它被注入到多个模块中，所有模块都只能访问一个特定的实例。这就是为什么在不同的控制器之间共享数据是非常方便的。

工厂

现在让我们来谈谈AngularJS中的工厂

首先让我们看一下语法:

app.js:

var app = angular.module('FactoryExample',[]);
var factoryController = app.controller('FactoryController', FactoryController);
var factoryExampleOne = app.factory('NameOfTheFactoryOne', NameOfTheFactoryOne);
var factoryExampleTwo = app.factory('NameOfTheFactoryTwo', NameOfTheFactoryTwo);

//first implementation where it returns a function
function NameOfTheFactoryOne(){
   var factory = function(){
      return new SomeService();
    }
   return factory;
}

//second implementation where an object literal would be returned
function NameOfTheFactoryTwo(){
   var factory = {
      getSomeService : function(){
          return new SomeService();
       }
    };
   return factory;
}

现在在控制器中使用上述两个:

 var factoryOne = NameOfTheFactoryOne() //since it returns a function
 factoryOne.someMethod();

 var factoryTwo = NameOfTheFactoryTwo.getSomeService(); //accessing the object
 factoryTwo.someMethod();

工厂特点:

这种类型的服务遵循工厂设计模式。工厂可以被认为是创建新对象或方法的中心场所。 这不仅可以生成单例服务，还可以生成可定制的服务。 .service()方法是一个工厂，它总是生成相同类型的服务，即单例服务。没有简单的方法来配置它的行为。.service()方法通常用作不需要任何配置的快捷方式。

还有一种方法可以返回构造函数，这样你就可以在工厂中返回可更新的类，像这样:

function MyObjectWithParam($rootScope, name) {
  this.$rootScope = $rootScope;
  this.name = name;
}
MyObjectWithParam.prototype.getText = function () {
  return this.name;
};

App.factory('MyObjectWithParam', function ($injector) {
  return function(name) { 
    return $injector.instantiate(MyObjectWithParam,{ name: name });
  };
}); 

你可以在控制器中做这个，它使用MyObjectWithParam:

var obj = new MyObjectWithParam("hello"),

完整的例子如下: http://plnkr.co/edit/GKnhIN?p=preview

这里是谷歌小组页面，讨论的地方: https://groups.google.com/forum/ !味精/角度/ 56 sdorweoqg / b8hdPskxZXsJ

You can understand the difference with this analogy - Consider the difference between a normal function that will return some value and constructor function that will get instantiated using new keyword.So creating factory is just similar to create normal function that will return some value(primitive or an object) whereas creating service is like creating constructor function(OO class) of which we can create instance using new keyword. The only thing to notice is here is that when we use Service method to create services it will automatically create instance of it using dependency injection mechanism supported by AngularJS

对于工厂，你实际上是在工厂内部创建一个对象并返回它。 对于该服务，您只有一个使用this关键字进行定义的标准函数 函数。 在提供程序中，你定义了一个$get，它可以用来获取返回的对象 数据。