(原)Java动态署理实现（简单AOP实现）

(原)Java动态代理实现（简单AOP实现）
本文介绍了简单Aop实现的方法，意在抛砖引玉。

首先是简单的Aspect接口

package org.aspect;/** * 切面接口 */public interface Aspect {/** * 事先执行 */public void doBefore();/** * 事后执行 */public void doAfter();}

然后是代理工厂

package org.aspect;import java.lang.reflect.Proxy;import java.util.ArrayList;import java.util.List;/** * 代理工厂类 */public class DynamicProxyFactory {/** * 私有构造方法 */private DynamicProxyFactory() {}/** * 工厂方法 *  * @param instance 代理目标类实例对象 * @param aspect 切面对象 */public static Object newInstance(Object instance, Aspect aspect) {List<Aspect> aspectList = new ArrayList<Aspect>();aspectList.add(aspect);return newInstance(instance, aspectList);}/** * 工厂方法 *  * @param instance 代理目标类实例对象 * @param aspectList 切面集合 */public static Object newInstance(Object instance, List<Aspect> aspectList) {SimpleInvocationHandler hander = new SimpleInvocationHandler();hander.setAspectList(aspectList);hander.setSource(instance);return Proxy.newProxyInstance(instance.getClass().getClassLoader(),   instance.getClass().getInterfaces(),   hander);}}

最后是代理执行类

package org.aspect;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.util.List;/** * 代理委托接口实现 */public class SimpleInvocationHandler implements InvocationHandler {private Object source = null;private List<Aspect> aspectList = null;public Object getSource() {return source;}public void setSource(Object source) {this.source = source;}public List<Aspect> getAspectList() {return aspectList;}public void setAspectList(List<Aspect> aspectList) {this.aspectList = aspectList;}/** * 委托方法 *  * @param proxy 代理对象 * @param method 代理方法 * @param args 方法参数 */public Object invoke(Object proxy, Method method, Object[] args)throws Throwable {for (Aspect aspect : aspectList) {aspect.doBefore();}Object retObj = method.invoke(getSource(), args);for (int index = aspectList.size() - 1; index >= 0; index--) {aspectList.get(index).doAfter();}return retObj;}}

测试代码

public interface Student {public void sayHello();}import org.aspect.Aspect;public class StudentAspectOne implements Aspect {@Overridepublic void doAfter() {System.out.println("do After One");}@Overridepublic void doBefore() {System.out.println("do Before One");}}import org.aspect.Aspect;public class StudentAspectTwo implements Aspect{@Overridepublic void doAfter() {System.out.println("do After Two");}@Overridepublic void doBefore() {System.out.println("do Before Two");}}public class StudentImpl implements Student {@Overridepublic void sayHello() {System.out.println("Student");}}import java.util.ArrayList;import java.util.List;import org.aspect.Aspect;import org.aspect.DynamicProxyFactory;public class Test {public static void main(String[] args) {List<Aspect> aspectList = new ArrayList<Aspect>();aspectList.add(new StudentAspectOne());aspectList.add(new StudentAspectTwo());Student s = (Student)DynamicProxyFactory.newInstance(new StudentImpl(), aspectList);s.sayHello();}}

执行Test，控制台返回

do Before One
do Before Two
Student
do After Two
do After One
1 楼 zxlsky1314 2010-09-21   学习了~~~ 2 楼 rainsilence 2010-09-23   这个zxlsky1314 写道学习了~~~
这些只是最简单的啦。可以对第一个接口进行扩展

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