下面就相當于把two對象賦值給three，two和three的信息就會一模一樣 ~~~ package obj.a6; class Cat{ String name; int age; String color; public void set(String name,int age,String color){ this.name=name; this.age=age; this.color=color; } public String toString(){ return "姓名："+name+"\t年齡："+age+"\t顏色："+color; } public Cat abc(){ return this; } } public class Test { public static void main(String[] args){ Cat one=new Cat(); Cat two=new Cat(); one.set("第一只貓", 5, "黑色"); two.set("第二只貓", 6, "白色"); Cat three=new Cat(); three=two.abc();//相當于three=two System.out.println(one); System.out.println(two); System.out.println(three); } } ~~~