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(); }}

输出

• 配置xxx=com.iot.proxy.aopframework.ProxyFactoryBean
  

输出为：

com.sun.proxy.$Proxy0
clear before at 0
clear cost total 0

• 配置xxx=java.util.ArrayList

输出为：

java.util.ArrayList

可以看出，只改变配置文件，就可改变代码的运行结果，从而达到灵活的效果

总结

以上就是本文关于Java实现AOP功能的封装与配置的小框架实例代码的全部内容，希望对大家有所帮助。感兴趣的朋友可以继续参阅本站其他相关专题，如有不足之处，欢迎留言指出。感谢朋友们对本站的支持！