Java 不可变类

 1 public class ImmuteDemo {
 2     private String name;  //String 为不可变类
 3     private Date date;    //Date 为可变类
 4 
 5     public ImmuteDemo(String name,Date date){
 6         this.name = name;
 7         this.date = new Date(date.getTime()); //对输入对象，进行拷贝
 8    //  date.setTime(2101);  改变输入对象，并不影响成员date的值
 9     }
10 
11     public String getName(){
12         return name;
13     }
14 
15     public Date getDate(){
16         return new Date(date.getTime());
17     }
18 
19     public static void main(String[] args) {
20         Date date = new Date();
21         ImmuteDemo immuteDemo = new ImmuteDemo("zhang san",date);
22     }
23 }
24