JAVA的接口多态

 1 interface dao {
 2     public static final int i = 10;
 3 
 4     public void add();
 5     public void delete();
 6 }
 7 
 8 class userDao implements dao {
 9     // 实现接口中的方法
10     @Override
11     public void add() {
12         System.out.println("增加成员成功");
13     }
14 
15     @Override
16     public void delete() {
17         System.out.println("删除成员成功");
18     }
19 }
20 
21 public class Demo {
22     public static void main(String[] args) {
23         dao d = new userDao();
24         d.add();
25     }
26 }