Let’s create a simple spring application and add logging aspect to be invoked on based on pointcuts information passed in <aop:before/> xml configuration. This example is also available with Java configuration using AspectJ @Before annotation in the application Spring AOP AspectJ @Before Annotation Advice Example.
Configuring Spring AOP Before Advice using aop namespace <aop:before/> and <aop:config>
In this example, we are using <aop:*/> namespace of XML configuration spring framework. We have to add aop namespace in the XML configuration file for application context for <aop:before/> advice in this application. Let’s see our aop configuration for before advice in this example.
<aop:config> <aop:aspect ref="loggingAspect"> <!-- all public methods with any arguments of any type and any return type of all classes in the com.doj.aopapp.service package --> <aop:pointcut expression="execution(* com.doj.aopapp.service.*.*(..))" id="logForAllMethods"/> <!-- all public methods whose name are transfer() with taking three arguments of any type and any return type of all classes in the com.doj.aopapp.service package --> <aop:pointcut expression="execution(* com.doj.aopapp.service.*.transfer(*,*,*))" id="logForAllTransfer"/> <aop:before method="beforeAdviceForAllMethods" pointcut-ref="logForAllMethods"/> <aop:before method="beforeAdviceForTransferMethods" pointcut-ref="logForAllTransfer"/> </aop:aspect> </aop:config>
Pointcut expressions
1. Following pointcut expression for before advice is valid for all public methods with any arguments of any type and any return type of all classes in the com.doj.aopapp.service package.
<aop:pointcut expression="execution(* com.doj.aopapp.service.*.*(..))" id="logForAllMethods"/>
2. Following pointcut expression for before advice is valid for all public methods whose name are transfer() with taking three arguments of any type and any return type of all classes in the com.doj.aopapp.service package.
<aop:pointcut expression="execution(* com.doj.aopapp.service.*.transfer(*,*,*))" id="logForAllTransfer"/>
Spring AOP Before Advice Example
Let’s create an example for a before advice, using xml configuration using <aop:before/> namespace.
Spring AOP Maven Dependencies
<properties> <spring.version>4.3.7.RELEASE</spring.version> <aspectj.version>1.8.9</aspectj.version> </properties> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>${aspectj.version}</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> <version>${aspectj.version}</version> </dependency> </dependencies>
ApplicationContext Configuration file based on XML Config
applicationContext.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" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <aop:config> <aop:aspect ref="loggingAspect"> <!-- all public methods with any arguments of any type and any return type of all classes in the com.doj.aopapp.service package --> <aop:pointcut expression="execution(* com.doj.aopapp.service.*.*(..))" id="logForAllMethods"/> <!-- all public methods whose name are transfer() with taking three arguments of any type and any return type of all classes in the com.doj.aopapp.service package --> <aop:pointcut expression="execution(* com.doj.aopapp.service.*.transfer(*,*,*))" id="logForAllTransfer"/> <aop:before method="beforeAdviceForAllMethods" pointcut-ref="logForAllMethods"/> <aop:before method="beforeAdviceForTransferMethods" pointcut-ref="logForAllTransfer"/> </aop:aspect> </aop:config> <bean id="transferService" class="com.doj.aopapp.service.TransferServiceImpl"/> <bean id="loggingAspect" class="com.doj.aopapp.aspect.LoggingAspect"/> </beans>
<aop:config/> element
A section (compartmentalization) of AOP-specific configuration (including aspects, pointcuts, etc).
<aop:aspect/> element
A named aspect definition.
<aop:pointcut/> element
A named pointcut definition.
<aop:before/> element
A before advice definition.
Target method of Service class on which aspects needs to apply
TransferService.java
/** * */ package com.doj.aopapp.service; /** * @author Dinesh.Rajput * */ public interface TransferService { void transfer(String accountA, String accountB, Long amount); Double checkBalance(String account); Long withdrawal(String account, Long amount); void diposite(String account, Long amount); }
TransferServiceImpl.java
/** * */ package com.doj.aopapp.service; /** * @author Dinesh.Rajput * */ public class TransferServiceImpl implements TransferService { @Override public void transfer(String accountA, String accountB, Long amount) { System.out.println(amount+" Amount has been tranfered from "+accountA+" to "+accountB); } @Override public Double checkBalance(String account) { return new Double(50000); } @Override public Long withdrawal(String account, Long amount) { return amount; } @Override public void diposite(String account, Long amount) { System.out.println(amount+" Amount has been diposited to "+account); } }
Aspect class “LoggingAspect”:
Write aspect class and methods to be executed as advice.
LoggingAspect.java
/** * */ package com.doj.aopapp.aspect; import org.aspectj.lang.JoinPoint; /** * @author Dinesh.Rajput * */ public class LoggingAspect { /** * Declaring before advice * @param jp * @throws Throwable */ public void beforeAdviceForAllMethods(JoinPoint jp) throws Throwable { System.out.println("****LoggingAspect.beforeAdviceForAllMethods() " + jp.getSignature().getName()); } /** * Declaring before advice for all transfer methods whose taking three arguments of any type * of all classes in the package com.doj.aopapp.service * @param jp * @throws Throwable */ public void beforeAdviceForTransferMethods(JoinPoint jp) throws Throwable { System.out.println("****LoggingAspect.beforeAdviceForTransferMethods() " + jp.getSignature().getName()); } }
Test Class for Spring AOP Before Advice Configuration and Execution
Now let’s see how to run and what would be output of this application when above configured aspects execute on given pointcut information.
/** * */ package com.doj.aopapp.test; import org.springframework.context.ConfigurableApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import com.doj.aopapp.service.TransferService; /** * @author Dinesh.Rajput * */ public class Main { /** * @param args */ public static void main(String[] args) { ConfigurableApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml"); TransferService transferService = applicationContext.getBean(TransferService.class); transferService.transfer("accountA", "accountB", 50000l); System.out.println("Available balance: " +transferService.checkBalance("accountA")); transferService.diposite("accountA", 50000l); System.out.println("Withdrawal amount: " +transferService.withdrawal("accountB", 40000l)); applicationContext.close(); } }
Output on the Console:
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@179d3b25: startup date [Tue Mar 07 18:55:52 IST 2017]; root of context hierarchy
Mar 07, 2017 6:55:52 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [applicationContext.xml]
****LoggingAspect.beforeAdviceForAllMethods() transfer
****LoggingAspect.beforeAdviceForTransferMethods() transfer
50000 Amount has been tranfered from accountA to accountB
****LoggingAspect.beforeAdviceForAllMethods() checkBalance
Available balance: 50000.0
****LoggingAspect.beforeAdviceForAllMethods() diposite
50000 Amount has been diposited to accountA
****LoggingAspect.beforeAdviceForAllMethods() withdrawal
Withdrawal amount: 40000
Mar 07, 2017 6:55:52 PM org.springframework.context.support.ClassPathXmlApplicationContext doClose
INFO: Closing org.springframework.context.support.ClassPathXmlApplicationContext@179d3b25: startup date [Tue Mar 07 18:55:52 IST 2017]; root of context hierarchy
Analyse the output, all join points execute with given information in this example.
Project Structure
Application Source Code
Spring AOP Before Advice Example using XML Config on GitHub.
- Spring AOP Interview Questions and Answers
- Spring AOP-Introduction to Aspect Oriented Programming
- @Aspect Annotation in Spring
- Advices in Spring AOP
- Spring AOP JoinPoints and Advice Arguments
- Spring AOP-Declaring pointcut Expressions with Examples
- Spring AOP XML configuration
- Spring AOP XML Schema based Example
- Spring AOP AspectJ @Before Annotation Advice Example
- Spring AOP AspectJ @After Annotation Advice Example
- Spring AOP After Advice Example using XML Config
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- Spring Transaction Management
- Spring Declarative Transaction Management Example
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