代理的应用（AOP）

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实现AOP功能的封装与配置

工厂类BeanFactory负责创建目标类或者代理类的实例对象，并通过配置文件

实现切换，其getBean方法根据参数字符串返回一个相应的实例对象，如果参数字符串

在配置文件中对应的类名不是ProxyFactoryBean,则直接返回该类的实例对象，

否则，返回该类实例对象的getProxy方法，返回一个代理对象

BeanFactory的构造方法接受代表配置文件的输入流对象，配置文件格式如下

#xxx= java.util.ArrayList

xxx= com.sdut.ProFactoryBean

xxx.target= java.util.ArrayList

xxx.advice= com.sdut.MyAdvice

ProxyFactoryBean充当动态生成代理的工厂，需要为工厂提供目标，和通知

程序如下：

BeanFactory.java bean工厂

publicclass BeanFactory {

//创建配置文件对象

Propertiesprop = new Properties();

publicBeanFactory(InputStream ips){

try{

prop.load(ips);

}catch (IOException e) {

//TODO Auto-generated catch block

e.printStackTrace();

}

publicObject getBean(String name){

StringclassName = prop.getProperty(name);

//创建className的字节码对象

Object obj;

try{

Classclazz = Class.forName(className);

//创建字节码对象所对应类的实例

obj= clazz.newInstance();

if(objinstanceof ProxyFactoryBean){

//为代理工厂送去目标，和消息

ProxyFactoryBeanproxyFactoryBean = (ProxyFactoryBean)obj;

//获取advice,target;

MyAdviceadvice = (MyAdvice)Class.forName(prop.getProperty(name +".advice")).newInstance();

Objecttarget = Class.forName(prop.getProperty(name +".target")).newInstance();

proxyFactoryBean.setAdvice(advice);

proxyFactoryBean.setTarget(target);

//开始创建代理对象

Objectproxy = proxyFactoryBean.getProxy();

returnproxy;

}

else{

returnobj;

}

}catch (Exception e) {

//TODO Auto-generated catch block

e.printStackTrace();

}

returnnull;

}

ProxyFactoryBean.java 代理工厂

publicclass ProxyFactoryBean {

privateObject target ;

privateAdvice advice;

publicObject getTarget() {

returntarget;

}

publicvoid setTarget(Object target) {

this.target= target;

}

publicAdvice getAdvice() {

returnadvice;

}

publicvoid setAdvice(Advice advice) {

this.advice= advice;

}

publicObject getProxy(){

Objectproxy3 = Proxy.newProxyInstance(target.getClass().getClassLoader(),

target.getClass().getInterfaces(),newInvocationHandler(){

@Override

publicObject invoke(Object proxy, Method method,

Object[]args) throws Throwable {

advice.getBeginTime(method);

ObjectretVal = method.invoke(target, args);

advice.getEndTime(method);

returnretVal;

}

});

returnproxy3;

}

测试类AopFrameworkTest.java

publicclass AopFramewrokTest {

publicstatic void main(String[] args) throws IOException {

//读取配置文件

InputStreamips =AopFramewrokTest.class.getResourceAsStream("config.properties");

Objectobj = new BeanFactory(ips).getBean("xxx");

System.out.println(obj.getClass().getName());

ips.close();

Collectioncollection = (Collection)obj;

collection.add("kk");

}