Java -- 基础 -- 动态代理

1、JDK 代理方式 -- HelloService.java

package com.sample.modules.jdk;

public interface HelloService {
    void sayHello();
}

2、JDK 代理方式 -- HelloServiceImpl.java

package com.sample.modules.jdk;

public class HelloServiceImpl implements HelloService {
    @Override
    public void sayHello() {
        System.out.println("hello world!");
    }
}

3、JDK 代理方式 -- ProxyHandler.java

package com.sample.modules.jdk;

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

public class ProxyHandler implements InvocationHandler{

    private Object subject;

    public ProxyHandler(Object subject){
        this.subject = subject;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("before");
        method.invoke(subject, args);
        System.out.println("after");
        return null;
    }
}

4、JDK 代理方式 -- ProxyTest.java

package com.sample.modules.jdk;

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

public class ProxyTest {

    public static void main(String[] args) {
        //1.被代理类
        HelloServiceImpl helloService = new HelloServiceImpl();
        //2.执行器
        InvocationHandler handler = new ProxyHandler(helloService);
        //3.代理类
        HelloService helloInterface = (HelloService) Proxy.newProxyInstance(handler.getClass().getClassLoader(), helloService.getClass().getInterfaces(), handler);
        helloInterface.sayHello();
    }
}

5、Cglib 代理方式 -- HelloService.java

package com.sample.modules.cglib;

public class HelloService {

    public void sayHello() {
        System.out.println("hello world!");
    }
}

6、Cglib 代理方式 -- ProxyHandler.java

package com.sample.modules.cglib;

import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.reflect.Method;

public class ProxyHandler implements MethodInterceptor {

    @Override
    public Object intercept(Object sub, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("======插入前置通知======");
        Object object = methodProxy.invokeSuper(sub, objects);
        System.out.println("======插入后者通知======");
        return object;
    }
}

7、Cglib 代理方式 -- ProxyTest.java

package com.sample.modules.cglib;

import net.sf.cglib.proxy.Enhancer;

public class ProxyTest {

    public static void main(String[] args) {
        // 通过CGLIB动态代理获取代理对象的过程
        Enhancer enhancer = new Enhancer();
        // 设置enhancer对象的父类
        enhancer.setSuperclass(HelloService.class);
        // 设置enhancer的回调对象
        enhancer.setCallback(new ProxyHandler());
        // 创建代理对象
        HelloService proxy = (HelloService) enhancer.create();
        // 通过代理对象调用目标方法
        proxy.sayHello();
    }
}