Aspect-Oriented Programing (AOP) Overview

According to the Spring tutorial by King God's Spring 07: "AOP Made Simple" (qq.com)

1. Understanding AOP

   Aspect-Oriented Programming (AOP) refers to a programming paradigm that enables unified maintenance of program functionalities through pre-compilation and runtime dynamic proxies. AOP extends OOP principles and represents a crucial concept in Spring framework development. It functions as a functional prgoramming derivative model that isolates various components of business logic, thereby reducing coupling between different parts of an application, enhancing reusability, and improving overall development efficiency.

2. Practical Applications of AOP

   • Implementation via Spring API Interfaces

     <!-- Configure AOP -->
     <aop:config>
         <!-- Define pointcut: expression specifies where to apply, execution(* com.wjj.service.UserServiceImpl.*(..)) -->
         <aop:pointcut id="pointcut" expression="execution(* com.wjj.service.UserServiceImpl.*(..))"/>
         <aop:advisor advice-ref="after" pointcut-ref="pointcut"/>
         <aop:advisor advice-ref="before" pointcut-ref="pointcut"/>
     </aop:config>
     
     

   • Custom AOP Implementation

     <bean id="diy" class="com.wjj.diy.DiyPointcut" />
     
     <aop:config>
         <!-- Define custom aspect, reference to class -->
         <aop:aspect ref="diy">
             <!-- Define pointcut -->
             <aop:pointcut id="pointcut" expression="execution(* com.wjj.diy.DiyPointcut.*(..))"/>
             <!-- Define advice -->
             <aop:before method="before" pointcut-ref="pointcut"/>
             <aop:after method="after" pointcut-ref="pointcut"/>
         </aop:aspect>
     </aop:config>
     
     

3. AOP Implementation Using Annotations

public class AnnotationPinot {
    @Before("execution(* com.wjj.service.UserServiceImpl.*(..))")
    public void before() {
        System.out.println("Before============");
    }
    
    @After("execution(* com.wjj.service.UserServiceImpl.*(..))")
    public void after() {
        System.out.println("================After");
    }
    
    @Around("execution(* com.wjj.service.UserServiceImpl.*(..))")
    public void around(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("Before Around");
        Object proceed = pjp.proceed();
        System.out.println("After Around");
    }
}

<!-- Enable auto-proxy support, default is JDK proxy (proxy-target-class="false"), use CGLIB (proxy-target-class="true") -->
<aop:aspectj-autoproxy proxy-target-class="false"/>
<!-- Alternative approach -->
<bean id="annotationPinot" class="com.wjj.diy.AnnotationPinot"/>