我对js类继承的尝试
/** * * 用于类继承 * User: yxx * Date: 10-4-14 * Time: 上午11:01 */var Class = function (window) { function apply(o, c) { if (o && c && typeof c == 'object') { for (var p in c) { o[p] = c[p]; } } return o; } /** *顶层基类 */ function Base() { } Base.superClass = Object; Base.prototype.is = function (type) { return this instanceof type; }; /** * 在构造函数中使用,类似java语法中的super * 如果父类中也调用了Super则递归下去只到Base * 调用Super等this.constructor.superClass.apply(this, arguments); * ps:由于super是关键字所以首字母大写 * @param args */ Base.prototype.Super = function (args) { this.__super__ = (this.__super__ || this.constructor).superClass;//取得父类构造函数 this.__super__.apply(this, arguments);//执行父类构造函数 delete this.__super__; }; /** * 继承一个类 * @param supClass 父类 * @param instances 实例方法和属性 * @param statics 静态方法和属性 */ function extend(supClass, instances, statics) { if (typeof supClass != "function") { statics = instances; instances = supClass; supClass = Base; } else if (supClass == Object) { supClass = Base; } else if (!supClass.superClass) { supClass.extend(Base, supClass.prototype); } else { delete this.extend; } var spp = supClass.prototype; function PC() {//子类原型构造函数(prototype constructor) } PC.prototype = spp;//从父类继承实例方法和属性 this.prototype = new PC();// 连接原型链完成继承 apply(this.prototype, instances);// 绑定实例方法和属性 apply(this, statics);// 绑定静态方法和属性 this.superClass = supClass;// 父类 this.prototype.superClass = spp;// 父类(原形) this.prototype.constructor = this; } function create(supClass, instances, statics) { var C = instances && instances.constructor;// 构造函数 if (C == Object || typeof C != "function") { C = function Constructor() { }; } else if (typeof instances == "function") { C = instances; } C.extend = extend;//为了不污染基础类没有把该方法直接绑定到Function.prototype上 C.extend(supClass, instances, statics); return C; } return { create:create, extend:function(supClass,subClass, instances, statics){ extend.call(subClass,supClass,instances,statics); } }}(window);//1.直接创建一个类默认继承Basevar Person = Class.create({constructor:function (name, age){this.name = name;this.age = age;}});//2.创建一个类并继承Pesson.var User = Class.create(Person,function (name, age,sex){this.Super(name, age);this.sex = sex;});//3.构造函数，function Teacher(name, age,sex){ this.Super(name, age); this.sex = sex;}//继承PessonClass.extend(Person,Teacher);//3.直接创建一个类默认继承Basevar Stu = Class.create({ constructor:function (name, age,sex,no){ this.Super(name, age,sex); this.no = no; }, getAge:function(){ return this.age; }});//更改父类为User.只有默认继承的父类为Base时才可以更改父类且只能改一次Stu.extend(User);//testvar p = new Person("张三",20);var u = new User("李四",40,"女");var s = new Stu("凤姐",70,男","10001");alert(p.name);alert(u.name);alert(s.name);alert(s.getAge());alert(s.superClass.age);//访问被覆盖的父类属性或方法alert(p instanceof Person);alert(u instanceof Person);alert(s instanceof Person);alert(s instanceof User);