angular.extend(dst,src)，在我实验的1.2.16版本上是支持深拷贝的。但是最新的API显示，这个方法是不支持深拷贝的。
另外，第二个参数src支持多个对象。
var user3 = angular.extend(user1,user2);会把user2的所有属性都拷贝到user1上，并且把user1复制给user3
var user3 = angular.extend({},user1,user2);这种使用方式，会保留原始对象，把user1与user2进行整合，在复制给user3.
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <script src="http://apps.bdimg.com/libs/angular.js/1.2.16/angular.min.js"></script> </head> <body ng-app="myApp"> <div ng-controller="myCtrl"> {{ user1 }} {{ user2 }} {{ user3 }} {{ user4 }} {{ user5 }} </div> <script type="text/javascript"> angular.module("myApp",[]) .controller("myCtrl",function($scope){ var user1 = {"name":"xingoo"}; var user2 = {"age":30}; var user3 = angular.extend(user1,user2); // var user3 = angular.extend({},user1,user2); $scope.user1 = user1; $scope.user2 = user2; $scope.user3 = user3; var user4 = new Object(); user4.name = "xingoo"; user4.age = 30; user4.mother = user1; var user5 = new Object(); angular.extend(user5,user4); $scope.user4 = user4; $scope.user5 = user5; }); </script> </body> </html>
原文：http://www.cnblogs.com/feng18/p/5139901.html