1.constructor方法

   class Star{
         constructor(uname,age){
             this.uname=uname;
             this.age=age;
         }
         sing(song){
            console.log(this.uname+song);
         }
     }
     var ldh=new Star("刘德华");
     var zxy=new Star("张学友")
     ldh.sing("冰雨")