标签：advice val null factory throw exception ant arraylist block
内容
java基础巩固笔记 - 实现AOP功能的封装与配置的小框架
设计（目录）：
XXX = java.util.ArrayList中
代码
Advice接口
MyAdvice类
BeanFactory类
ProxyFactoryBean类
AopFrameWorkTest类
输出
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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
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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
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);
}
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));
}
}
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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;
}
}
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;
}
}
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();
}
}
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配置
xxx=com.iot.proxy.aopframework.ProxyFactoryBean
输出为：
com.sun.proxy.$Proxy0clear before at 0clear 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
标签：advice val null factory throw exception ant arraylist block
原文地址：http://www.cnblogs.com/Autumn-R/p/7094247.html
