Springaop 简明教程

Spring AOP - Annotation Based After Throwing Advice

@AfterThrowing 是一种通知类型，它确保在方法抛出一个异常时运行一个通知。以下是 @AfterThrowing 通知的语法。

@AfterThrowing is an advice type which ensures that an advice runs if the method throws an exception. Following is the syntax of @AfterThrowing advice.

Syntax

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

其中，

Where,

  1. @AfterThrowing − Mark a function as an advice to be executed before method(s) covered by Pointcut, if the method throws an exception.

  2. Pointcut − Provides an expression to select a function.

  3. execution( expression ) − Expression covering methods on which advice is to be applied.

  4. throwing − Name of the exception to be returned.

为了理解与 @AfterThrowing 相关建议已经提到的概念，我们来写一个将实施 @AfterThrowing 建议的示例。若要使用少量的建议来编写示例，我们先来设置一个可行的 Eclipse IDE，然后使用以下步骤来创建一个 Spring 应用程序：

To understand the above-mentioned concepts related to @AfterThrowing Advice, let us write an example which will implement @AfterThrowing Advice. To write our example with few advices, let us have a working Eclipse IDE in place and use the following steps to create a Spring application.

Step

Description

1

Update the project Student created under chapter Spring AOP - Application.

2

Update the bean configuration and run the application as explained below.

以下是 Logging.java 文件的内容。这实际上是方面模块的一个示例，它定义了在各个点调用的方法。

Following is the content of Logging.java file. This is actually a sample of aspect module, which defines the methods to be called at various points.

package com.tutorialspoint;

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

以下是 Student.java 文件的内容。

Following is the content of the Student.java file.

package com.tutorialspoint;

public class Student {
   private Integer age;
   private String name;

   public void setAge(Integer age) {
      this.age = age;
   }
   public Integer getAge() {
      System.out.println("Age : " + age );
      return age;
   }
   public void setName(String name) {
      this.name = name;
   }
   public String getName() {
      System.out.println("Name : " + name );
      return name;
   }
   public void printThrowException(){
      System.out.println("Exception raised");
      throw new IllegalArgumentException();
   }
}

以下是 MainApp.java 文件的内容。

Following is the content of the MainApp.java file.

package com.tutorialspoint;

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 。

Following is the configuration file Beans.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: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.tutorialspoint.Student">
      <property name = "name"  value = "Zara" />
      <property name = "age"  value = "11"/>
   </bean>

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

</beans>

Run Project

创建源和配置文件后，运行您的应用程序。在应用程序中右键单击 MainApp.java 并使用 run as Java Application 命令。如果您的应用程序一切正常，它将打印以下消息。

Once you are done creating the source and configuration files, run your application. Rightclick on MainApp.java in your application and use run as Java Application command. If everything is fine with your application, it will print the following message.

Exception raised
Method Signature: void com.tutorialspoint.Student.printThrowException()
Exception: java.lang.IllegalArgumentException
Exception in thread "main" java.lang.IllegalArgumentException

   at com.tutorialspoint.Student.printThrowException(Student.java:25)
   ...