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Spring AOP - After Returning Advice
  • 时间:2024-12-22

Spring AOP - XML Based After Returning Advice


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After is an advice type which ensures that an advice runs after the method execution only if the method completes successfully. Following is the syntax of after advice.

Syntax


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

Where,

    PointCut-id − id of the PointCut.

    methodName − Method name of the function to be called after a called function returns successfully.

To understand the above-mentioned concepts related to After Returning Advice, let us write an example which will implement After Returning advice. To write our example with few advices, let us have a working Ecppse IDE in place and use the following steps to create a Spring apppcation −

Step Description
1 Update the project Student created under chapter Spring AOP - Apppcation.
2 Update the bean configuration and run the apppcation as explained below.

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;

pubpc class Logging {
   /** 
      * This is the method which I would pke to execute
      * when any method returns.
   */
   pubpc void afterReturningAdvice(Object retVal){
      System.out.println("Returning:" + retVal.toString() );
   }
}

Following is the content of the Student.java file.


package com.tutorialspoint;

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

Following is the content of the MainApp.java file.


package com.tutorialspoint;

import org.springframework.context.ApppcationContext;
import org.springframework.context.support.ClassPathXmlApppcationContext;

pubpc class MainApp {
   pubpc static void main(String[] args) {
      ApppcationContext context = new ClassPathXmlApppcationContext("Beans.xml");
      
      Student student = (Student) context.getBean("student");
      student.getName();
      student.getAge();     
   }
}

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:config>
      <aop:aspect id = "log" ref = "logging">
         <aop:pointcut id = "selectAll" 
         expression = "execution(* com.tutorialspoint.*.*(..))"/>
         <aop:after-returning pointcut-ref = "selectAll" 
            method = "afterReturningAdvice" returning = "retVal"/>         
      </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>

Run Project

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


Name : Zara
Returning : Name
Age : 11
Exception raised
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