Java實現AOP功能的封裝與配置的小架構執行個體代碼，javaaop

Java實現AOP功能的封裝與配置的小架構執行個體代碼，javaaop

本文通過是動態代理實現的AOP功能的封裝與配置的小架構.加深對動態代理和AOP編程的理解

設計

根據設定檔的鍵xxx對應的值(類全名)建立相應類的對象。

若且唯若xxx對應的值為com.iot.proxy.aopframework.ProxyFactoryBean時，則產生相應的動態代理類對象。代理對象的目標類和通知實作類別分別由xxx.target和xxx.advice配置

設定檔

config.propertiest位於aopframework包下

• xxx代表要載入的類
• xxx.advice代表通知介面的某個實作類別
• xxx.target代表委託類

#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,有如下幾個類/介面：

• BeanFactory,用於讀取設定檔，根據配置建立相應的對象
• ProxyFactoryBean,用於組建代理程式對象，含有兩個私人屬性:目標和通知
• Advice,通知介面，用於把切面的代碼以對象的形式傳遞給InvocationHandler的的invoke方法
• MyAdvice,Advice介面的一個實作類別，列印執行方法前的時間及執行耗時
• AopFrameWorkTest，測試效果
  

代碼Advice介面

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類

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類

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類

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類

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();}}

輸出

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

輸出為：

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

• 配置xxx=java.util.ArrayList

輸出為：

java.util.ArrayList

可以看出，只改變更配置置檔案，就可改變代碼的運行結果，從而達到靈活的效果

總結

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