Java实现AOP功能的封装与配置的小框架实例代码

2019-11-26 10:18:40

字体：大中小

来源：转载

供稿：网友

本文通过是动态代理实现的AOP功能的封装与配置的小框架.加深对动态代理和AOP编程的理解

设计

根据配置文件的键xxx对应的值(类全名)创建相应类的对象。

当且仅当xxx对应的值为com.iot.proxy.aopframework.ProxyFactoryBean时，则生成相应的动态代理类对象。代理对象的目标类和通知实现类分别由xxx.target和xxx.advice配置

配置文件

config.propertiest位于aopframework包下

xxx代表要加载的类
xxx.advice代表通知接口的某个实现类
xxx.target代表委托类

#xxx=java.util.ArrayList
xxx=com.iot.proxy.aopframework.ProxyFactoryBean
xxx.advice=com.iot.proxy.MyAdvice
xxx.target=java.util.ArrayList

包:com.iot.proxy.aopframework,有如下几个类/接口：

BeanFactory,用于读取配置文件，根据配置创建相应的对象
ProxyFactoryBean,用于生成代理对象，含有两个私有属性:目标和通知
Advice,通知接口，用于把切面的代码以对象的形式传递给InvocationHandler的的invoke方法
MyAdvice,Advice接口的一个实现类，打印执行方法前的时间及执行耗时
AopFrameWorkTest，测试效果

代码

Advice接口

package com.iot.proxy.aopframework;import java.lang.reflect.Method;/** * Created by brian on 2016/2/2. */public interface Advice {  void beforeMethod(Method method);  void aftereMethod(Method method);}

MyAdvice类

package com.iot.proxy.aopframework;import java.lang.reflect.Method;/** * Created by brian on 2016/2/2. */public class MyAdvice implements Advice{	long beginTime = 0 ;	@Override	  public void beforeMethod(Method method) {		System.out.println(method.getName()+" before at "+beginTime);		beginTime = System.currentTimeMillis();	}	@Override	  public void aftereMethod(Method method) {		long endTime = System.currentTimeMillis();		System.out.println(method.getName()+" cost total "+ (endTime-beginTime));	}}

BeanFactory类

package com.iot.proxy.aopframework;import java.io.IOException;import java.io.InputStream;import java.util.Properties;/** * Created by brian on 2016/2/2. */public class BeanFactory {	Properties properties = new Properties();	public BeanFactory(InputStream inputStream){		try {			properties.load(inputStream);		}		catch (IOException e) {			e.printStackTrace();		}	}	public Object getBean(String name){		String className = properties.getProperty(name);		Object bean = null;		try {			Class clazz = Class.forName(className);			bean = clazz.newInstance();		}		catch (ClassNotFoundException e) {			e.printStackTrace();		}		catch (InstantiationException e) {			e.printStackTrace();		}		catch (IllegalAccessException e) {			e.printStackTrace();		}		if (bean instanceof ProxyFactoryBean){			ProxyFactoryBean proxyFactoryBean = (ProxyFactoryBean)bean;			Advice advice = null;			Object target = null;			try {				advice = (Advice) Class.forName(properties.getProperty(name+".advice")).newInstance();				target = Class.forName(properties.getProperty(name+".target")).newInstance();			}			catch (InstantiationException e) {				e.printStackTrace();			}			catch (IllegalAccessException e) {				e.printStackTrace();			}			catch (ClassNotFoundException e) {				e.printStackTrace();			}			proxyFactoryBean.setAdvice(advice);			proxyFactoryBean.setTarget(target);			Object proxy = ((ProxyFactoryBean) bean).getProxy();			return proxy;		}		return bean;	}}

ProxyFactoryBean类

package com.iot.proxy.aopframework;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;/** * Created by brian on 2016/2/3. */public class ProxyFactoryBean {	private Object target;	private Advice advice;	public Object getProxy(){		Object proxy = Proxy.newProxyInstance(		        target.getClass().getClassLoader(),		        target.getClass().getInterfaces(),		        new InvocationHandler() {			@Override			          public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {				advice.beforeMethod(method);				Object retVal = method.invoke(target,args);				advice.aftereMethod(method);				return retVal;			}		}		);		return proxy;	}	public Object getTarget() {		return target;	}	public void setTarget(Object target) {		this.target = target;	}	public Advice getAdvice() {		return advice;	}	public void setAdvice(Advice advice) {		this.advice = advice;	}}

AopFrameWorkTest类

package com.iot.proxy.aopframework;import java.io.InputStream;import java.util.Collection;/** * Created by brian on 2016/2/3. */public class AopFrameWorkTest {	public static void main(String[] args) {		InputStream inputStream = AopFrameWorkTest.class.getResourceAsStream("config.properties");		Object bean = new BeanFactory(inputStream).getBean("xxx");		System.out.println(bean.getClass().getName());		((Collection) bean).clear();	}}