Spring AOP - 基于 XML 抛出建议后

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After- throwing是一种建议类型，它确保仅当方法通过抛出异常退出时，建议才会在方法执行后运行。以下是抛出后建议的语法。

句法

<aop:config>
   <aop:aspect id = "log" ref = "logging">
      <aop:pointcut id = "PointCut-id" expression = "execution( expression )"/>    
      <aop:after-throwing pointcut-ref = "PointCut-id" throwing = "ex" 
         method = "methodName"/>
   </aop:aspect>
</aop:config>

在哪里，

• PointCut-id - 切点的 id。

• ex - 要抛出的异常。

• methodName - 当被调用函数抛出异常并退出时要调用的函数的方法名称。

为了理解上述与 After Throwing Advice 相关的概念，让我们编写一个示例来实现 After Throwing Advice。为了编写我们的示例并提供一些建议，让我们有一个可用的 Eclipse IDE，并使用以下步骤创建一个 Spring 应用程序 -

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

package com.tutorialspoint;

public class Logging {
   /**
      * This is the method which I would like to execute
      * if there is an exception raised.
   */
   public void afterThrowingAdvice(IllegalArgumentException ex) {
      System.out.println("There has been an exception: " + ex.toString());   
   } 
}

以下是Student.java文件的内容。

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。

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。

<?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:config>
      <aop:aspect id = "log" ref = "logging">
         <aop:pointcut id = "selectAll" 
         expression = "execution(* com.tutorialspoint.*.*(..))"/>
         <aop:after-throwing pointcut-ref = "selectAll" 
            throwing = "ex" method = "afterThrowingAdvice"/>         
      </aop:aspect>
   </aop:config>

   <!-- 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>

运行项目

创建完源文件和配置文件后，运行您的应用程序。右键单击应用程序中的 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。

Exception raised
There has been an exception: java.lang.IllegalArgumentException
Exception in thread "main" java.lang.IllegalArgumentException
   at com.tutorialspoint.Student.printThrowException(Student.java:25)
...