- Spring AOP Tutorial
- Spring AOP - Home
- Spring AOP - Overview
- Spring AOP - Environment Setup
- Spring AOP - Core Concepts
- Spring AOP - Advice Types
- Spring AOP - Implementations
- By XML Configuration Examples
- Spring AOP - Application
- Spring AOP - Pointcut Methods
- Spring AOP - Before Advice
- Spring AOP - After Advice
- Spring AOP - After Returning Advice
- Spring AOP - After Throwing Advice
- Spring AOP - Around Advice
- By Annotation Examples
- Spring AOP - Application
- Spring AOP - Pointcut Methods
- Spring AOP - Before Aspect
- Spring AOP - After Advice
- Spring AOP - After Returning Advice
- Spring AOP - After Throwing Advice
- Spring AOP - Around Advice
- Spring AOP Advanced
- Spring AOP - Proxy
- Spring AOP - Custom Annotation
- Spring AOP Useful Resources
- Spring AOP - Quick Guide
- Spring AOP - Useful Resources
- Spring AOP - Discussion
Spring AOP - XML Based Before Advice
Before is an advice type which ensures that an advice runs before the method execution. Following is the syntax of before advice.
Syntax
<aop:config> <aop:aspect id = "log" ref = "logging"> <aop:pointcut id = "PointCut-id" expression = "execution( expression )"/> <aop:before pointcut-ref = "PointCut-id" method = "methodName"/> </aop:aspect> </aop:config>
Where,
PointCut-id − id of the PointCut.
methodName − Method name of the function to be called before a called function.
To understand the above-mentioned concepts related to Before Advice, let us write an example, which will implement Before 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. |
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; public class Logging { /** * This is the method which I would like to execute * before a selected method execution. */ public void beforeAdvice(){ System.out.println("Going to setup student profile."); } }
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(); } }
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.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.Student.getName(..))"/> <aop:before pointcut-ref = "selectAll" method = "beforeAdvice"/> </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 source and configuration files, run your application. Right-click 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.
Going to setup student profile. Name : Zara Age : 11