小慶的Spring學習筆記三

jdk和cglib動態代理

1.jdk動態代理

package com.yqg.proxy;

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

/**
 * @author yqg
 * @date 2019-02-18 22:04
 */
public class JdkProxy implements InvocationHandler {

    private Object target;

    /**
     * 綁定業務對象，並返回一個代理類
     */
    public Object bind(Object target){
        this.target = target;
        return Proxy.newProxyInstance(target.getClass().getClassLoader(),target.getClass().getInterfaces(),this);
    }

    /**
     *
     * @param proxy
     * @param method
     * @param args
     * @return
     * @throws Throwable
     */
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("你好,小慶");
        Object result = method.invoke(target,args);
        System.out.println("要好好學習喲");
        return result;
    }
}

　　

 @org.junit.Test
    public void JdkTest(){
        People people = new QingGuo();
        JdkProxy jdkProxy = new JdkProxy();
        People qingguo = (People) jdkProxy.bind(people);
        qingguo.drink();
        qingguo.eat();
    }

　　2.cglib代理

package com.yqg.proxy;

import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;

import java.lang.reflect.Method;

/**
 * @author yqg
 * @date 2019-02-18 22:05
 */
public class CgLibProxy implements MethodInterceptor {
    private Object target;

    /**
     *
     * 綁定業務對象
     */

    public Object getInstance(Object target){
        this.target = target;
        /**
         * 建立增長器，設置代理類的父類和回調方法
         */
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(this.target.getClass());
        enhancer.setCallback(this);
        return enhancer.create();
    }
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("cglib代理");
       return methodProxy.invokeSuper(o,objects);
    }
}

　　

 @org.junit.Test
    public void CglibTest(){
        People people = new QingGuo();
        CgLibProxy cgLibProxy = new CgLibProxy();
        People p = (People) cgLibProxy.getInstance(people);
        p.eat();
        p.drink();
    }

　　

3.二者區別

jdk動態代理使用反射機制，cglib使用的是字節碼機制，前者屬於java包，後者屬於spring 框架。