Spring AOP基於註解的AfterThrowing


@AfterThrowing是一種通知類型,可以確保在方法拋出異常時運行一個通知。 以下是@AfterThrowing通知的語法:

語法

@AfterThrowing(pointcut="execution(* com.yiibai.Student.*(..))", throwing= "error")
public void afterThrowingAdvice(JoinPoint jp, Throwable error){
   System.out.println("Method Signature: "  + jp.getSignature());  
   System.out.println("Exception: "+error);  
}

在上面的語法示例中 -

  • @AfterReturning - 如果方法返回成功,則將函數標記爲在切入點覆蓋的方法之前執行的通知。
  • @Pointcut - 將函數標記爲切入點
  • @After - 將函數標記爲在切入點覆蓋的方法之後執行的通知。
  • execution( expression ) - 涵蓋應用通知的方法的表達式。
  • throwing - 返回的異常名稱。

要了解上面提到的@AfterThrowing通知相關的概念,我們寫一個Spring AOP基於註解的應用例子,它將使用基於註解配置實現通知。打開並使用Eclipse IDE,並按照以下步驟創建一個Spring應用程序:

  1. 更新在Spring AOP應用實例中創建過的Student項目。
  2. 更新bean配置並運行應用程序,如下所述。

整個項目的目錄結構如下所示 -

Spring AOP基於註解的AfterThrowing

下面是Logging.java文件的內容。 這實際上是一個Aspect模塊的樣本,它定義了在各個點被調用的方法。

package com.yiibai;

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.JoinPoint;  
import org.aspectj.lang.annotation.AfterThrowing;  

@Aspect
public class Logging {

   /** 
    * This is the method which I would like to execute
    * after a selected method execution throws exception.
    */
   @AfterThrowing(pointcut="execution(* com.yiibai.Student.*(..))", throwing= "error")
   public void afterThrowingAdvice(JoinPoint jp, Throwable error){
      System.out.println("[afterThrowingAdvice] Method Signature: "  + jp.getSignature());  
      System.out.println("[afterThrowingAdvice] Exception: "+error);  
   }
}

以下是Student.java文件的內容:

package com.yiibai;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainApp {
   public static void main(String[] args) {
      ApplicationContext context = 
             new ClassPathXmlApplicationContext("Beans.xml");

      Student student = (Student) context.getBean("student");

      student.printThrowException();     
   }
}

以下是MainApp.java文件的內容:

package com.yiibai;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainApp {
   public static void main(String[] args) {
      ApplicationContext context = 
             new ClassPathXmlApplicationContext("Beans.xml");

      Student student = (Student) context.getBean("student");

      student.printThrowException();     
   }
}

以下是配置文件Beans.xml文件的內容:

<?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:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
    http://www.springframework.org/schema/aop 
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">

   <aop:aspectj-autoproxy/>

   <!-- Definition for student bean -->
   <bean id="student" class="com.yiibai.Student">
      <property name="name"  value="minsu" />
      <property name="age"  value="24"/>      
   </bean>

   <!-- Definition for logging aspect -->
   <bean id="logging" class="com.yiibai.Logging"/> 

</beans>

運行項目

完成創建源代碼和配置文件後,運行應用程序。右鍵單擊應用程序中的MainApp.java,並使用運行方式作爲Java應用程序命令。 如果您的應用程序一切正常,這將打印以下消息:

Exception raised
[afterThrowingAdvice] Method Signature: void com.yiibai.Student.printThrowException()
[afterThrowingAdvice] Exception: java.lang.IllegalArgumentException
Exception in thread "main" java.lang.IllegalArgumentException
    at com.yiibai.Student.printThrowException(Student.java:25)
    at com.yiibai.Student$$FastClassBySpringCGLIB$$e9280b4b.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:58)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)
    at com.yiibai.Student$$EnhancerBySpringCGLIB$$bb5ffc0.printThrowException(<generated>)
    at com.yiibai.MainApp.main(MainApp.java:16)