Java静态代理总结

总结：

1. 真实对象（被代理对象）和代理对象都要实现同一个接口
2. 代理对象要代理真实角色（被代理对象）

优点：

1. 代理对象可以补充真实对象（被代理对象）所要做的事情
2. 真实对象（被代理对象）只需要关注自己做的事情

// 被代理的接口
interface Study {
    void readBook();
}

// 真实对象（被代理对象）
class You implements Study {
    @Override
    public void readBook() {
        System.out.println("I like Studing!");
    }
}

// 代理类
class School implements Study {
    // 真实对象类（被代理对象）
    private Study target;

    public School(Study target) {
        this.target = target;
    }


    @Override
    public void readBook() {
        before();
        this.target.readBook();
        after();
    }

    private void before() {
        System.out.println("buy books.");
    }

    private void after() {
        System.out.println("supply foods.");
    }
}

public class StacticProxy {
    public static void main(String[] args) {
        // 传入真实对象类（被代理对象）给代理类
        School School = new School(new You());
        School.readBook();
    }
}

执行结果：

静态代理实现打日志功能

• 被代理的接口

public interface ActionService {
    String add();

    String query();

    String delete();

    String update();
}

• 被代理类

public class ActionServiceImpl implements ActionService {
    @Override
    public String add() {
        return "add";
    }

    @Override
    public String query() {
        return "query";
    }

    @Override
    public String delete() {
        return "delete";
    }

    @Override
    public String update() {
        return "update";
    }
}

• 代理类

package com.wcj.proxy;

import com.wcj.service.ActionService;
import com.wcj.service.impl.ActionServiceImpl;

public class ActionProxyService implements ActionService {
    private ActionServiceImpl actionService;

    public ActionProxyService(ActionServiceImpl actionService) {
        this.actionService = actionService;
    }

    @Override
    public String add() {
        System.out.println("====>add");
        return actionService.add();
    }

    @Override
    public String query() {
        System.out.println("====>query");
        return actionService.query();
    }

    @Override
    public String delete() {
        System.out.println("====>delete");
        return actionService.delete();
    }

    @Override
    public String update() {
        System.out.println("====>update");
        return actionService.update();
    }
}

• 测试方法

public class testProxy {
    public static void main(String[] args) {
        ActionServiceImpl actionService = new ActionServiceImpl();
        ActionProxyService actionProxyService = new ActionProxyService(actionService);
        actionProxyService.add();
        actionProxyService.delete();
        actionProxyService.update();
        actionProxyService.query();
    }
}

• 测试结果