1、切面场景

无侵入的实现功能增强

2、实现

切面类的实现

需要使用注解@Aspect和Componet来实现，

环绕通知的作用在返回的student的sname后面拼接around字符串。

后置通知的作用在入参后面拼接idididdi，然后打印日志

@Aspect
@Component
public class StudentBeforeAspect {

    @Pointcut("@annotation(com.nio.annotation.StudentBeforeAopAnnotation)")
    public void studentBefortAspect(){}

    @AfterReturning(value = "studentBefortAspect()")
    public void addInfo(JoinPoint joinPoint){
        final Object[] args = joinPoint.getArgs();
        if (ObjectUtils.isNotEmpty(args)){
            for (Object arg : args) {
                if (arg instanceof String){
                    String id = String.valueOf(arg) + "idididdi";
                    System.out.println("id is " + id);
                }
            }
        }
    }

    @Around(value = "studentBefortAspect()")
    public Object addInfo(ProceedingJoinPoint proceedingJoinPoint){
        StudentInfo result = null;
        final Object[] args = proceedingJoinPoint.getArgs();
        try {
            Object proceed = proceedingJoinPoint.proceed(args);
            if (Objects.nonNull(proceed)) {
                if (proceed instanceof StudentInfo) {
                    result = (StudentInfo) proceed;
                    result.setSname(result.getSname() + "aroud");
                    return result;
                }
            }
        } catch (Throwable e) {
            throw new RuntimeException(e);
        }
        return result;
    }
}

注解的实现

自定义注解来实现切点方法的定位

@Target(ElementType.METHOD)
@Documented
@Retention(RetentionPolicy.RUNTIME)
public @interface StudentBeforeAopAnnotation {
}

切点方法

    @StudentBeforeAopAnnotation
    public StudentInfo getById(String id) {
        return studentDomainService.getById(id);
    }

运行结果