Usage

1. Create the Project

2. pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>spring_aop</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.3.24.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>4.3.24.RELEASE</version>
        </dependency>
    </dependencies>
</project>

3. Code

3.1. Business-Logic Class

• HelloWorld

public class Calc
{
    public int div(int a, int b)
    {
        System.out.println(a / b);
        return a /  b;
    }

}

3.2. Aspect Class

@Aspect// indicates an aspect class
public class LogAspects
{
    // Pointcut: the target method that needs to be proxied.
    @Pointcut("execution(public int com.example.test.aop.Calc.*(..))")
    public void pointCut()
    {
    }

    // Before advice: runs before the target method.
    @Before("pointCut()")
    public void logStart(JoinPoint joinPoint)
    {
        System.out.println("logStart: parameters:"+ Arrays.asList(joinPoint.getArgs()));
    }

    // After advice: runs after the target method.
    @After("pointCut()")
    public void logEnd(JoinPoint joinPoint)
    {
        System.out.println("logEnd: methodName:" + joinPoint.getSignature().getName());
    }


    // Return advice: runs after the target method returns normally.
    @AfterReturning(value = "pointCut()", returning = "result")
    public void logReturn(Object result)
    {
        System.out.println("logReturn: result:" + result);
    }

    // Exception advice: runs when the target method throws an exception.
    @AfterThrowing(value = "pointCut()", throwing = "exception")
    public void logException(Exception exception)
    {
        System.out.println("logException: exceptino:" + exception.getMessage());
    }

    // Around advice: jointPoint.proceed(). Manually invoke the target method.
}

3.3. Configuration Class

@EnableAspectJAutoProxy// enable Spring AOP
@Configuration
public class AopConfig
{
    // Add both the aspect and the business logic to the Spring container.
    @Bean
    public Calc calc()
    {
        return new Calc();
    }

    @Bean
    public LogAspects logAspects()
    {
        return new LogAspects();
    }

    public static void main(String[] args)
    {
        // Need to obtain it from the Spring container.
        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(AopConfig.class);
        Calc calc = applicationContext.getBean(Calc.class);
        calc.div(10,10);
        System.out.println("==================");
        calc.div(10,0);

    }
}