jdk动态代理与cglib动态代理简单样例

最新推荐文章于 2025-04-10 17:09:06 发布

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#动态代理

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本文介绍了Java中两种动态代理技术：JDK动态代理和CGLIB动态代理。通过示例展示了如何使用这两种技术为接口和服务实现类创建代理对象，并在运行时拦截方法调用。

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概述: jdk动态代理代理的是接口, 根据具体的实现类动态生成接口的实现类

cglib动态代理代理的是类, 根据具体的实现类生成实现类的子类

接口与实现类:

1.接口:IUserService

package proxy;

/**
 * @author: lybing
 * @create: 2018-04-10-11:24
 * @desc: jdk proxy
 */

public interface IUserService {

    /**
     * method test
     */
    void test();
}

2.实现类UserServiceImpl

package proxy;

/**
 * @author: lybing
 * @create: 2018-04-10-11:25
 * @desc: userService implements
 */

public class UserServiceImpl implements IUserService{

    @Override
    public void test() {
        System.out.println("do test...");
    }
}

jdk动态代理:

package proxy;

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

/**
 * @author: lybing
 * @create: 2018-04-10-11:27
 * @desc: jdk proxy
 */

public class JdkProxyUserService implements InvocationHandler{

    private Object target;

    public JdkProxyUserService(IUserService target) {
        this.target = target;
    }

    public IUserService getProxy(){
        return (IUserService) Proxy.newProxyInstance(JdkProxyUserService.class.getClassLoader(),
                target.getClass().getInterfaces(), this);
    }

    @Override
    public Object invoke(Object o, Method method, Object[] objects) throws Throwable {
        System.out.println("---------BEFORE INVOKE---------");
        // 调用者为具体实例对象
        Object result = method.invoke(target, objects);
        System.out.println("---------AFTER INVOKE---------");
        return result;
    }

    public static void main(String[] args) {
        IUserService userService = new UserServiceImpl();
        IUserService proxy = new JdkProxyUserService(userService).getProxy();
        System.out.println(userService.getClass().getName());
        System.out.println(proxy.getClass().getName());
        proxy.test();
    }
}

cglib动态代理:

package 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: lybing
 * @create: 2018-04-10-11:43
 * @desc: cglib proxy
 */

public class CglibProxyUserService implements MethodInterceptor{

    private Object target;

    public CglibProxyUserService(Object object){
        this.target = object;
    }

    public IUserService getProxy(){
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(target.getClass());
        enhancer.setCallback(this);
        return (IUserService)enhancer.create();
    }

    @Override
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("=======BEFORE INVOKE======");
        // 调用者为具体实例对象
        Object result = method.invoke(target, objects);
        System.out.println("=======AFTER INVOKE======");
        return result;
    }

    public static void main(String[] args) {
        IUserService userService = new UserServiceImpl();
        IUserService proxy = new CglibProxyUserService(userService).getProxy();
        System.out.println(userService.getClass().getName());
        System.out.println(proxy.getClass().getName());
        proxy.test();
    }
}