用reflect proxy把你的商业方法执行推迟,并放到其他地方执行。
概念:1.proxy instance 代理实例
2.invocationHandler 调用处理器
编写商业对象和接口:
public interface BusinessInterface
{
public void processBusiness();
}
public class BusinessObject implements BusinessInterface
{
public void processBusiness(){
System.out.println("this is the business code!");
}
};
编写调用处理器,商业方法就在这里被调用:
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
public class Myhandler implements InvocationHandler
{
Object businessObject;
Myhandler(Object delegate){
businessObject = delegate;
}
public Object invoke(Object proxy , Method method , Object[] args) throws IllegalAccessException ,InvocationTargetException{
Object o = null;
System.out.println("log: start execute business");//这里可以用log4j,那么记录日志就和商业方法分开了
//if(IsPermission(user)){//可以考虑在这里进行安全控制
//Transaction.begin();//可以考虑在这里进行事务处理控制
//long begin = System.CurrentTimeMillis();
o = method.invoke(businessObject,args);//执行商业方法
//long end = System.CurrenTimeMillis();
//System.out.println(">>log:"+ (end - begin));//进行性能统计,
//Transaction.commit();//
//}
System.out.println("log: end execute business");
return o;
}
};
构造代理实例并用代理实例来执行商业方法
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;
public class AoP
{
public static void main(String[] args)
{
BusinessInterface businessObject = new BusinessObject();
//构造一个handler
InvocationHandler handler = new Myhandler(businessObject);
//构造代理实例
BusinessInterface proxy = (BusinessInterface)Proxy.newProxyInstance(businessObject.getClass().getClassLoader(),businessObject.getClass().getInterfaces(),handler);
//用代理实例来执行商业方法,那么代理会调用myhandler的invoke()来执行这个方法
proxy.processBusiness();
}
}