代理模式（动态）

public interface IDAO {
    public int save();
    public int remove();
    public int modify();
    public int findAll();
}

public class DeptDAO implements IDAO{
    @Override
    public int save() {
        return 1;
    }

    @Override
    public int remove() {
        return 2;
    }

    @Override
    public int modify() {
        return 3;
    }

    @Override
    public int findAll() {
        return 4;
    }
}

package com.bh.proxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class MyProxy implements InvocationHandler {
    //要被代理的类
    private Object delegateEnhanced;

    /*绑定要被代理的类*/
    public Object bind(Object delegate){
        this.delegateEnhanced = delegate;
        Object createdObject = Proxy.newProxyInstance(delegate.getClass().getClassLoader(),
                //要增强被代理类的所有方法的功能
                delegate.getClass().getInterfaces(), this);

        return createdObject;


    }
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("开始spa==============");
        Object result = method.invoke(this.delegateEnhanced, args);
        System.out.println("结束spa==============");
        return result;
    }
}

public class Test {
    public static void main(String[] args) {
      //查看$Proxy0.class的方法
      // System.getProperties().put("sun.misc.ProxyGenerator.saveGeneratedFiles","true");
        //原厂产品
        DeptDAO deptDAO = new DeptDAO();
        //代理商
        MyProxy myProxy = new MyProxy();
        //代理商 在原厂产品上增强
        IDAO deptDaoEnhance = (IDAO)myProxy.bind(deptDAO);
        int i = deptDaoEnhance.findAll();//执行时生成了一个$Proxy0.class里面调用代理类的invoke方法
        System.out.println(i);
    }
}

开始spa==============
结束spa==============
4