Spring AOP：访问目标方法的参数

访问目标方法 最简单的做法就是定义增强处理方法时将第一个参数定义为JoinPoint类型，当该增强处理方法被调用时，该JoinPoint参数就代表了织入增强处理的连接点。JoinPoint里包含了如下几个常用的方法：

Object[ ] getArgs( )返回执行目标方法时的参数Signature getSignature( )返回被增强的方法的相关信息Object getTarget( )返回被织入增强处理的目标对象Object getThis( )返回AOP框架为目标对象生成的代理对象

Person.java :

public interface Person {public String sayHello(String name);public void eat(String food);}

Chinese.java :

@Componentpublic class Chinese implements Person {@Overridepublic String sayHello(String name) {System.out.println("sayHello方法被调用...");return name+" Hello,Spring AOP";}@Overridepublic void eat(String food) {System.out.println("我正在吃:"+food);}}

FourAdviceTest.java :

@Aspectpublic class FourAdviceTest {@Around("execution(* com.bean.*.*(..))")public Object processTx(ProceedingJoinPoint jp) throws Throwable{System.out.println("Around增强:执行目标方法之前，模拟开始事务...");Object[] args=jp.getArgs();if(args!=null && args.length>0 && args[0].getClass()==String.class){args[0]="被改变的参数";}Object rvt=jp.proceed(args);System.out.println("Around增强:执行目标方法之后，模拟结束事务...");return rvt+" 新增的内容";}@Before("execution(* com.bean.*.*(..))")public void authority(JoinPoint jp){System.out.println("Before增强:模拟执行权限检查...");System.out.println("Before增强:被织入增强处理的目标方法为："+jp.getSignature().getName());System.out.println("Before增强：目标方法的参数为："+Arrays.toString(jp.getArgs()));System.out.println("Before增强:被织入增强处理的目标对象为："+jp.getTarget());}@AfterReturning(returning="rvt",pointcut="execution(* com.bean.*.*(..))")public void log(JoinPoint jp,Object rvt){System.out.println("AfterReturning增强：获取目标方法返回值："+rvt);System.out.println("AfterReturning增强：模拟记录日志功能...");System.out.println("AfterReturning增强：被织入增强处理的目标方法为:"+jp.getSignature().getName());System.out.println("AfterReturning增强：目标方法的参数为："+Arrays.toString(jp.getArgs()));System.out.println("AfterReturning增强:被织入增强处理的目标对象为："+jp.getTarget());}@After("execution(* com.bean.*.*(..))")public void release(JoinPoint jp){System.out.println("After增强：模拟方法结束后的释放资源...");System.out.println("After增强：被织入增强处理的目标方法为："+jp.getSignature().getName());System.out.println("After增强：目标方法的参数为："+Arrays.toString(jp.getArgs()));System.out.println("After增强: 被织入增强处理的目标对象为："+jp.getTarget());}}

bean.xml :

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"        xmlns:context="http://www.springframework.org/schema/context"        xmlns:aop="http://www.springframework.org/schema/aop"        xmlns:tx="http://www.springframework.org/schema/tx"        xsi:schemaLocation="http://www.springframework.org/schema/beans                 http://www.springframework.org/schema/beans/spring-beans-2.5.xsd                http://www.springframework.org/schema/context                 http://www.springframework.org/schema/context/spring-context-2.5.xsd                http://www.springframework.org/schema/tx                http://www.springframework.org/schema/tx/spring-tx-2.5.xsd                http://www.springframework.org/schema/aop                http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">            <context:component-scan base-package="com.bean">        <context:include-filter type="annotation"                  expression="org.aspectj.lang.annotation.Aspect"/>    </context:component-scan>        <aop:aspectj-autoproxy/>     </beans>

Test.java :

public class Test {public static void main(String[] args) {ApplicationContext ctx=new ClassPathXmlApplicationContext("bean.xml");Person p=(Person) ctx.getBean("chinese");System.out.println(p.sayHello("张三"));p.eat("西瓜");}}

运行程序，控制台输出：