静态代理模式

1.接口

public interface UserService {
    void add();
    void delete();
    void select();
}

2.被代理对象实现接口

public class UserServiceImpl implements UserService {
    public void add() {
        System.out.println("增加一个用户...");
    }

    public void delete() {
        System.out.println("删除一个用户");
    }

    public void select() {
        System.out.println("查询一个用户");
    }
}

3.代理对象实现接口

public class UserServiceProxy implements UserService {
    private UserService userService;

    public void setUserServiceProxy(UserService userService){
        this.userService=userService;
    }

    public void add() {
        log("add");
        userService.add();
    }
    public void delete() {
        log("delete");
        userService.delete();
    }
    public void select() {
        log("select");
        userService.select();
    }

    public void log(String msg){
        System.out.println("使用了"+msg+"方法");
    }
}

4.测试类

public class Client {
    public static void main(String[] args) {
        UserService userService = new  UserServiceImpl();
        UserServiceProxy proxy = new UserServiceProxy();
        proxy.setUserServiceProxy(userService);

        proxy.add();
    }
}