Spring AOP Around Advice Example

In this spring aop example, we will learn to use AOP around advice using <aop:around/> configuration. Methods configured as around advice, run before the methods, which match the pointcut expression passed as argument. At this stage you must make decision that original method should be called or not, because from here you can terminate the application flow and return a value directly without calling the original advised method.

In this example, We will create simple spring application, add logging aspect and then invoke aspect methods based on pointcuts information passed in <aop:around/> xml configuration.

Creating Spring AOP Around Advice

To create a around advice, using xml configuration, use <aop:around/> in below manner.

<aop:config> 
    <aop:aspect ref="loggingAspect">
        <aop:pointcut expression="execution(* com.howtodoinjava.app.service.impl.EmployeeManagerImpl.*(..))" id="loggingPointcuts"/>
        <!-- around advice -->
        <aop:around method="logAroundAllMethods" pointcut-ref="loggingPointcuts" />  
    </aop:aspect> 
</aop:config>

The advice method will have a method argument of type ProceedingJoinPoint which can be used call advised method.

public void logAroundAllMethods(ProceedingJoinPoint pjp) throws Throwable 
{
    System.out.println("****LoggingAspect.logAroundAllMethods() - Before method call");
    
    pjp.proceed();
    
    System.out.println("****LoggingAspect.logAroundAllMethods() - After method call");
}

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>

Add Spring AOP Configuration

In XML config file, you can add aop:config element to add AOP 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 ">

    <aop:config> 
        <aop:aspect ref="loggingAspect">
            <aop:pointcut expression="execution(* com.howtodoinjava.app.service.impl.EmployeeManagerImpl.*(..))" id="loggingPointcuts"/>
            <aop:around method="logAroundAllMethods" pointcut-ref="loggingPointcuts" />  
        </aop:aspect> 
    </aop:config> 
        
    <!-- 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 Aspect Class and Methods

Write aspect class and methods to be executed as advice.

package com.howtodoinjava.app.aspect;

import org.aspectj.lang.ProceedingJoinPoint;

public class LoggingAspect {

    public void logAroundAllMethods(ProceedingJoinPoint pjp) throws Throwable 
    {
        System.out.println("****LoggingAspect.logAroundAllMethods() - Before method call");
        
        pjp.proceed();
        
        System.out.println("****LoggingAspect.logAroundAllMethods() - After method call");
    }
}

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.logAroundAllMethods() - Before method call

Method getEmployeeById() called

****LoggingAspect.logAroundAllMethods() - After method call

****LoggingAspect.logAroundAllMethods() - Before method call

Method createEmployee() called

****LoggingAspect.logAroundAllMethods() - After method call

Clearly around aspect advices executed on relevant jointpoints.

Happy Learning !!

References:

Spring AOP Reference
AspectJ Project
Different Pointcut Expressions With Examples