AOP: Add Logging to Spring MVC Project

Add AspectJ JAR Files

Add AspectJ JAR file to web/WEB-INF/lib/aspectjweaver-1.8.13.jar

Enable AspectJ Auto Proxy

Add AspectJ Auto Proxy to spring-mvc-crud-demo-servlet.xml

<beans ...
    xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="
    ...
		http://www.springframework.org/schema/aop
		http://www.springframework.org/schema/aop/spring-aop.xsd">

	<!-- Add AspectJ Autoproxy support for AOP-->
	<!-- This is used for processing @Aspect classes -->
	<aop:aspectj-autoproxy />
</beans>

Create Aspect

Add Logging Aspect

@Aspect
@Component
public class CRMLoggingAspect {
  // setup logger
  private Logger logger = Logger.getLogger(getClass().getName());
}

Setup Pointcut Declaration

Create three seperate PointCut Declaration and join them together.

// setup pointcut declarations
    @Pointcut("execution(* com.luv2code.springdemo.controller.*.*(..))")
    private void forControllerPackage(){ }

    @Pointcut("execution(* com.luv2code.springdemo.dao.*.*(..))")
    private void forDaoPackage(){ }

    @Pointcut("execution(* com.luv2code.springdemo.service.*.*(..))")
    private void forServicePackage(){ }

    @Pointcut("forControllerPackage() || forDaoPackage() || forServicePackage()")
    private void forAppFlow(){}

Add @Before Advice

@Before(value = "forAppFlow()")
public void beforeAdvice(JoinPoint joinPoint){
  // display the method name
  String methodName = joinPoint.getSignature().toShortString();
  logger.info("========>> in @Before: Method Name: " + methodName);
  // display the args of the method
  Object[] args =  joinPoint.getArgs();
  for(Object o: args){
    logger.info("========>> Argument: "+ o.toString());
  }
}

Add @AfterReturning Advice

@AfterReturning(
  pointcut = "forAppFlow()",
  returning = "res")
public void afterReturning(JoinPoint joinPoint, Object res){
  // display the method name
  String methodName = joinPoint.getSignature().toShortString();
  logger.info("========>> in @AfterReturning: Method Name: " + methodName);
  logger.info("========>> Result: "+ res);
}

Log Example

Reference: [1]Udemy, Spring & Hibernate for Beginners (including SpringBoot)