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.
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>
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"/>
Let’s create an example for a before advice, using xml configuration using <aop:before/> namespace.
<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.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()); } }
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(); } }
Analyse the output, all join points execute with given information in this example.
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