使用Java的代理机制进行日志输出

示例代码如下:

//LogProxy.java

package com.gc.action;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

public class LogProxy implements InvocationHandler{
 private Logger logger = Logger.getLogger(this.getClass().getName());
 private Object delegate;
 //绑定代理对象
 public Object bind(Object delegate){
  this.delegate = delegate;
  return Proxy.newProxyInstance(delegate.getClass().getClassLoader(),
    delegate.getClass().getInterfaces(),this);
 }
 //针对接口编程
 public Object invoke(Object proxy,Method method,Object[] args) throws Throwable {
  Object result = null;
  try{
   //在方法调用前后进行日志输出
   logger.log(Level.INFO,args[0]+" 开始审核数据...");
   result = method.invoke(delegate, args);
   logger.log(Level.INFO,args[0]+" 审核数据结束...");
  }catch(Exception e){
   logger.log(Level.INFO,e.toString());
  }
  return result;
 }
}

//TimeBookInterface.java

package com.gc.impl;

//针对接口编程
public interface TimeBookInterface {
 public void doAuditing(String name);
}

//TimeBook.java

package com.gc.action;

import com.gc.impl.TimeBookInterface;

public class TimeBook implements TimeBookInterface {
 //审核数据的相关程序
 public void doAuditing(String name){
  System.out.println("审核程序");
 }
}

//TestHelloWorld.java

package com.gc.test;

import com.gc.action.LogProxy;
import com.gc.action.TimeBook;
import com.gc.impl.TimeBookInterface;

public class TestHelloWorld {
 public static void main(String[] args){
  //实现了对日志类的重用
  LogProxy logProxy = new LogProxy();
  TimeBookInterface timeBookProxy = (TimeBookInterface)logProxy.bind(new TimeBook());
  timeBookProxy.doAuditing("张三");
 }
}

运行结果:

[INFO ] 2009-11-01 23:23:39 com.gc.action.LogProxy - 张三 开始审核数据...
审核程序
[INFO ] 2009-11-01 23:23:39 com.gc.action.LogProxy - 张三 审核数据结束...