In this spring aop example, we will learn to use aspectj @Before
annotation. @Before
annotated methods run exactly before the all methods matching with pointcut expression.
In this example, We will create simple spring application, add logging aspect and then invoke aspect methods based on pointcuts information passed in @Before
annotation.
AspectJ @Before Annotation Usage
You can use @Before
annotation in below manner.
@Aspect public class LoggingAspect { @Before("execution(* com.howtodoinjava.app.service.impl.EmployeeManagerImpl.*(..))") public void logBeforeAllMethods(JoinPoint joinPoint) { ... } @Before("execution(* com.howtodoinjava.app.service.impl.EmployeeManagerImpl.getEmployeeById(..))") public void logBeforeGetEmployee(JoinPoint joinPoint) { ... } }
Project Structure

Spring AOP AspectJ Maven Dependencies
I have added spring core, spring aop and aspectj dependencies.
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd; <modelVersion>4.0.0</modelVersion> <groupId>com.howtodoinjava</groupId> <artifactId>SpringAOPExamples</artifactId> <version>0.0.1-SNAPSHOT</version> <name>Spring AOP Examples</name> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>1.8.9</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> <version>1.8.9</version> </dependency> </dependencies> </project>
Enable AspectJ Support
In XML config file, you can add aop:aspectj-autoproxy
element to enable @AspectJ
annotation support.
<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 "> <!-- Enable @AspectJ annotation support --> <aop:aspectj-autoproxy /> <!-- Employee manager --> <bean id="employeeManager" class="com.howtodoinjava.app.service.impl.EmployeeManagerImpl" /> <!-- Logging Aspect --> <bean id="loggingAspect" class="com.howtodoinjava.app.aspect.LoggingAspect" /> </beans>
Service methods on which aspects needs to be executed
EmployeeManager.java
and EmployeeManagerImpl.java
public interface EmployeeManager { public EmployeeDTO getEmployeeById(Integer employeeId); public List<EmployeeDTO> getAllEmployee(); public void createEmployee(EmployeeDTO employee); public void deleteEmployee(Integer employeeId); public void updateEmployee(EmployeeDTO employee); } public class EmployeeManagerImpl implements EmployeeManager { public EmployeeDTO getEmployeeById(Integer employeeId) { System.out.println("Method getEmployeeById() called"); return new EmployeeDTO(); } public List<EmployeeDTO> getAllEmployee() { System.out.println("Method getAllEmployee() called"); return new ArrayList<EmployeeDTO>(); } public void createEmployee(EmployeeDTO employee) { System.out.println("Method createEmployee() called"); } public void deleteEmployee(Integer employeeId) { System.out.println("Method deleteEmployee() called"); } public void updateEmployee(EmployeeDTO employee) { System.out.println("Method updateEmployee() called"); } }
Write AspectJ Annotated Class and Methods
Write aspectj annotated class and methods with pointcut information.
@Aspect public class LoggingAspect { @Before("execution(* com.howtodoinjava.app.service.impl.EmployeeManagerImpl.*(..))") public void logBeforeAllMethods(JoinPoint joinPoint) { System.out.println("****LoggingAspect.logBeforeAllMethods() : " + joinPoint.getSignature().getName()); } @Before("execution(* com.howtodoinjava.app.service.impl.EmployeeManagerImpl.getEmployeeById(..))") public void logBeforeGetEmployee(JoinPoint joinPoint) { System.out.println("****LoggingAspect.logBeforeGetEmployee() : " + joinPoint.getSignature().getName()); } @Before("execution(* com.howtodoinjava.app.service.impl.EmployeeManagerImpl.createEmployee(..))") public void logBeforeCreateEmployee(JoinPoint joinPoint) { System.out.println("****LoggingAspect.logBeforeCreateEmployee() : " + joinPoint.getSignature().getName()); } }
Test Spring AspectJ Configuration and Execution
Now let’s test whether above configured aspects execute on given pointcut information.
import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import com.howtodoinjava.app.model.EmployeeDTO; import com.howtodoinjava.app.service.EmployeeManager; public class TestMain { @SuppressWarnings("resource") public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); EmployeeManager manager = (EmployeeManager) context.getBean("employeeManager"); manager.getEmployeeById(1); manager.createEmployee(new EmployeeDTO()); } }
****LoggingAspect.logBeforeAllMethods() : getEmployeeById ****LoggingAspect.logBeforeGetEmployee() : getEmployeeById Method getEmployeeById() called ****LoggingAspect.logBeforeAllMethods() : createEmployee ****LoggingAspect.logBeforeCreateEmployee() : createEmployee Method createEmployee() called
Clearly aspect advices executed on revelant jointpoints.
Happy Learning !!
References:
Spring AOP Reference
@Before Annotation
@Aspect Annotation
AspectJ Annotation Config Example
Different Pointcut Expressions With Examples