动态代理-初级篇

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最近想总结一下java的动态代理，动态代理有很多种实现方案，下面介绍三种最常用的动态搭理方案：1.jdk自带动态代理2.javassist实现动态代理3.cglib实现动态代理

接口和实现类代码：

package com.java.day1.dynamicproxy.one;

public interface Interface {
	void doSomeThing();
}

 

package com.java.day1.dynamicproxy.one;

public class RealSubject   implements Interface{

	@Override
	public void doSomeThing() {
		System.out.println("do some things..");
	}
}

 jdk自带动态搭理实现

package com.java.day1.dynamicproxy.one;

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

public class JdkProxyHandler  implements InvocationHandler{
	//　这个就是我们要代理的真实对象
    private Object subject;
    //    构造方法，给我们要代理的真实对象赋初值
    public JdkProxyHandler(Object subject) {
        this.subject = subject;
    }
	@Override
	public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
		System.out.println("do otherthings..jdk..");
		return method.invoke(subject, args);
 	}
}

 

package com.java.day1.dynamicproxy.one;

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

public class JdkTest {

	public static void main(String[] args) {
		//被代理的类
		RealSubject rs = new RealSubject();
		// 代理增强类
		InvocationHandler ih = new JdkProxyHandler(rs);
		// 用java反射生成代理类
		Interface proxy = (Interface) Proxy.newProxyInstance(ih.getClass().getClassLoader(), rs.getClass().getInterfaces(), ih);
		proxy.doSomeThing();
	}

}

 javassist实现动态代理

package com.java.day1.dynamicproxy.one;

import java.lang.reflect.Method;

import javassist.util.proxy.MethodHandler;

public class JavassitInterceptor implements MethodHandler{
	private Object subject;
	public JavassitInterceptor(Object subject){
		this.subject = subject;
	}
	@Override
	public Object invoke(Object self, Method m, Method prosess, Object[] args) throws Throwable {
		System.out.println("do other thing..javassist.");
		return m.invoke(subject, args);
	}

}

 

package com.java.day1.dynamicproxy.one;


import javassist.util.proxy.ProxyFactory;
import javassist.util.proxy.ProxyObject;

public class javassistTest {

	public static void main(String[] args) throws Exception {
		//被代理的类
		RealSubject rs = new RealSubject();
		// 代理增强类
		JavassitInterceptor ih = new JavassitInterceptor(rs);
		// 用javassist反射生成代理类
	    ProxyFactory pf = new ProxyFactory();
	    pf.setInterfaces(rs.getClass().getInterfaces());
	   Class  proxyClass = pf.createClass();
	   Interface proxy = (Interface) proxyClass.newInstance();
	   ((ProxyObject)proxy).setHandler(ih);
	   proxy.doSomeThing();
 	}

}

 cglib实现动态搭理

package com.java.day1.dynamicproxy.one;

import java.lang.reflect.Method;

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

public class CglibInterceptor implements MethodInterceptor {
	private Object subject;
	public CglibInterceptor(Object subject){
		this.subject = subject;
	}
	@Override
	public  Object intercept(Object object, Method method, Object[] objects,  MethodProxy methodProxy) throws Throwable  {
		System.out.println("do other things..cglib...");
		return methodProxy.invoke(subject, objects);
	}

}

 

package com.java.day1.dynamicproxy.one;


import net.sf.cglib.proxy.Enhancer;

public class CgligTest {

	public static void main(String[] args) {
		//被代理的类
		RealSubject rs = new RealSubject();
		// 代理增强类
	    Enhancer enhancer = new Enhancer();
	    CglibInterceptor  ci = new CglibInterceptor(rs);
	    enhancer.setCallback(ci);
        enhancer.setInterfaces(rs.getClass().getInterfaces());	    
        Interface proxy = (Interface)enhancer.create();
        proxy.doSomeThing();
	}

}

 我还做了实验，但从创建来看jdk是最快的cglib最慢，但创建好后调用，javassist最快，jdk次之，不过是同一个数量级的，cglib最慢比其他2种慢5倍