java使用动态代理来实现AOP(日志记录)的实例代码
AOP（面向方面）的思想，就是把项目共同的那部分功能分离开来，比如日志记录，避免在业务逻辑里面夹杂着跟业务逻辑无关的代码
下面是一个AOP实现的简单例子：
首先定义一些业务方法：
复制代码代码如下:
/
CreatedwithIntelliJIDEA.
Author:wangjieemail:tiantian.china.2@gmail.com
Date:13-9-23
Time:下午3:49
/
publicinterfaceBussinessService{
publicStringlogin(Stringusername,Stringpassword);
publicStringfind();
}
publicclassBussinessServiceImplimplementsBussinessService{
privateLoggerlogger=Logger.getLogger(this.getClass().getSimpleName());
@Override
publicStringlogin(Stringusername,Stringpassword){
return"loginsuccess";
}
@Override
publicStringfind(){
return"findsuccess";
}
}
复制代码代码如下:
/
CreatedwithIntelliJIDEA.
Author:wangjieemail:tiantian.china.2@gmail.com
Date:13-9-24
Time:上午10:27
/
publicinterfaceWorkService{
publicStringwork();
publicStringsleep();
}
publicclassWorkServiceImplimplementsWorkService{
@Override
publicStringwork(){
return"worksuccess";
}
@Override
publicStringsleep(){
return"sleepsuccess";
}
}
实现InvocationHandler接口，使用map来存储不同的InvocationHandler对象，避免生成过多。
复制代码代码如下:
packagecom.wangjie.aoptest2.invohandler;
importjava.lang.reflect.InvocationHandler;
importjava.lang.reflect.Method;
importjava.lang.reflect.Proxy;
importjava.util.Arrays;
importjava.util.HashMap;
importjava.util.logging.Logger;
/
CreatedwithIntelliJIDEA.
Author:wangjieemail:tiantian.www.visa158.comchina.2@gmail.com
Date:13-9-23
Time:下午3:47
/
publicclassLogInvoHandlerimplementsInvocationHandler{
privateLoggerlogger=Logger.getLogger(this.getClass().getSimpleName());
privateObjecttarget;//代理目标
privateObjectproxy;//代理对象
privatestaticHashMap,LogInvoHandler>invoHandlers=newHashMap,LogInvoHandler>();
privateLogInvoHandler(){
}
/
通过Class来生成动态代理对象Proxy
@paramclazz
@return
/
publicsynchronizedstaticTgetProxyInstance(Classclazz){
LogInvoHandlerinvoHandler=invoHandlers.get(clazz);
if(null==invoHandler){
invoHandler=newLogInvoHandler();
try{
Ttar=clazz.newInstance();
invoHandler.setTarget(tar);
invoHandler.setProxy(Proxy.newProxyInstance(tar.getClass().getClassLoader(),
tar.getClass().getInterfaces(),invoHandler));
}catch(Exceptione){
e.printStackTrace();
}
invoHandlers.put(clazz,invoHandler);
}
return(T)invoHandler.getProxy();
}
@Override
publicObjectinvoke(Objectproxy,Methodmethod,Object[]args)throwsThrowable{
Objectresult=method.invoke(target,args);//执行业务处理
//打印日志
logger.info("____invokemethod:"+method.getName()
+";args:"+(null==args?"null":Arrays.asList(args).toString())
+";return:"+result);
returnresult;
}
publicObjectgetTarget(){
returntarget;
}
publicvoidsetTarget(Objecttarget){
this.target=target;
}
publicObjectgetProxy(){
returnproxy;
}
publicvoidsetProxy(Objectproxy){
this.proxy=proxy;
}
}
然后编写一个Test类测试：
复制代码代码如下:
/
CreatedwithIntelliJIDEA.
Author:wangjieemail:tiantian.china.2@gmail.com
Date:13-9-24
Time:上午9:54
/
publicclassTest{
publicstaticLoggerlogger=Logger.getLogger(Test.class.getwww.hunanwang.netSimpleName());
publicstaticvoidmain(String[]args){
BussinessServicebs=LogInvoHandler.getProxyInstance(BussinessServiceImpl.class);
bs.login("zhangsan","123456");
bs.find();
logger.info("--------------------------------------");
WorkServicews=LogInvoHandler.getProxyInstance(WorkServiceImpl.class);
ws.work();
ws.sleep();
logger.info("--------------------------------------");
BussinessServicebss=LogInvoHandler.getProxyInstance(BussinessServiceImpl.class);
bss.login("lisi","654321");
bss.find();
}
}
以后需要添加新的业务逻辑XXXService，只需要调用
XXXServicexs=LogInvoHandler.getProxyInstance(XXXServiceImpl.class);
即可。
也可以模仿Spring等框架的配置，把bean的类名配置在xml文件中，如：
然后在java代码中解析xml，通过Class.forName("com.wangjie.aoptest2.service.impl.BussinessServiceImpl");获得Class对象
然后通过LogInvoHandler.getProxyInstance(Class.forName("com.wangjie.aoptest2.service.impl.BussinessServiceImpl"));获得代理对象Proxy
再使用反射去调用代理对象的方法。
运行结果如下：
九月24,201311:08:03上午com.wangjie.aoptest2.invohandler.LogInvoHandlerinvoke
INFO:____invokemethod:login;args:[zhangsan,123456];return:loginsuccess
九月24,201311:08:03上午com.wangjie.aoptest2.invohandler.LogInvoHandlerinvoke
INFO:____invokemethod:find;args:null;return:findsuccess
九月24,201311:08:03上午com.wangjie.aoptest2.Testmain
INFO:--------------------------------------
九月24,201311:08:03上午com.wangjie.aoptest2.invohandler.LogInvoHandlerinvoke
INFO:____invokemethod:work;args:null;return:worksuccess
九月24,201311:08:03上午com.wangjie.aoptest2.invohandler.LogInvoHandlerinvoke
INFO:____invokemethod:sleep;args:null;return:sleepsuccess
九月24,201311:08:03上午com.wangjie.aoptest2.Testmain
INFO:--------------------------------------
九月24,201311:08:03上午com.wangjie.aoptest2.invohandler.LogInvoHandlerinvoke
INFO:____invokemethod:login;args:[lisi,654321];return:loginsuccess
九月24,201311:08:03上午com.wangjie.aoptest2.invohandler.LogInvoHandlerinvoke
INFO:____invokemethod:find;args:null;return:findsuccess
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