19-静态代理再理解

静态代理再理解

1.接口

package com.tian.demo02;

public interface UserService {
  public  void add();
  public  void delete();
  public  void update();
  public  void query();
}

2.UserServiceImpl

package com.tian.demo02;

public class UserServiceImpl implements UserService{
    public void add() {
        System.out.println("增加了一个用户");
    }

    public void delete() {
        System.out.println("删除了一个用户");
    }

    public void update() {
        System.out.println("更新了一个用户");
    }

    public void query() {
        System.out.println("查询了一个用户");
    }
}

3.UserSerivceProxy

• 不改动原有代码，实现日志的功能

package com.tian.demo02;

public class UserSerivceProxy implements UserService{
    private UserServiceImpl userService;

    public void setUserService(UserServiceImpl userService) {
        this.userService = userService;
    }

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

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

    public void update() {
        log("update");
        userService.update();
    }

    public void query() {
        log("query");
        userService.query();
    }
    //日志方法
    public void log(String msg){
        System.out.println("使用了"+msg+"方法");
    }
}

4.Client

package com.tian.demo02;

public class Client {
    public static void main(String[] args) {
        UserServiceImpl userService = new UserServiceImpl();
        UserSerivceProxy proxy = new UserSerivceProxy();
        proxy.setUserService(userService);
        proxy.add();
    }
}