静态代理，动态代理---笔记

• 静态代理

例如租房子。

public interface Leasing {
    public String doLeasing(String name,long money);
}

一般实现类

public class LeasingImpl implements Leasing {
    public String doLeasing(String name ,long money)
    {
        return name+"租到房，价格:"+money;
    }
}

中介的实现类

public class PreoxyLeasing implements Leasing {

    LeasingImpl mLeasImpl;
    public PreoxyLeasing( LeasingImpl mLeasImpl) {
        this.mLeasImpl =mLeasImpl;
    }

    @Override
    public String doLeasing(String name,long money) {
       getMoeyFromUser();
        System.out.println("用户多花了"+(money/2));
        getMoeyFromHouser();
        System.out.println("房东多花了"+(money/2));
        return name+"中介帮忙租到房子 价格："+money;
    }
    public void getMoeyFromUser() {
        System.out.println("收取用户的一半租金");
    }
    public void getMoeyFromHouser() {
        System.out.println("收取房东的一半租金");
    }
}

租客自己租房。

 Leasing mLeas = new LeasingImpl();
        System.out.println(mLeas.doLeasing("自己",1000l));

租客通过中介来租房

  Leasing mLeas = new LeasingImpl();   
 mLeas = new PreoxyLeasing(new LeasingImpl());
 System.out.println(mLeas.doLeasing("中介",1000l));

• 动态代理。

首先实现InvocationHandler接口，处理invoke方法，使用动态代理，调用每个方法都会执行invoke方法。

public class LeasingHandler implements InvocationHandler {
    Object mBase;

    public LeasingHandler(Object mBase) {
        this.mBase = mBase;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        //拦截方法
        if("doLeasing".equals(method.getName()))
        {
            {
                System.out.println("收用户一半的房租");
                System.out.println("收房主一半的房租");
                Long money = (Long) args[1];
                money +=money/2;
                // 帮忙租房子
                String things = (String) method.invoke(mBase,args[0], money);
                return things;
            }
        }
        return null;
    }
}