AspectJ的註解配置

@Aspect註解是不能夠通過類路徑自動檢測發現的，所以需要配合@Component註釋或者在xml配置bean

一個類中的@Aspect註解標識它爲一個切面，並且將自己從自動代理中排除（原因：不能陷入死循環）

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface MoocMethod {

    String value();

}


@Service
public class MoocBiz {

    @MoocMethod("MoocBiz save with MoocMethod.")
    public String save(String arg) {
        System.out.println("MoocBiz save : " + arg);
//      throw new RuntimeException(" Save failed!");
        return " Save success!";
    }

}

---

@Component
@Aspect
public class MoocAspect {
    //指定切點
    @Pointcut("execution(* com.imooc.aop.aspectj.biz.*Biz.*(..))")
    public void pointcut() {}
    //winin：一個範圍
    @Pointcut("within(com.imooc.aop.aspectj.biz.*)")
    public void bizPointcut() {}

    @Before("pointcut()")
    public void before() {
        System.out.println("Before.");
    }
    pointcut()爲存在@Pointcut的方法名，args（arg）傳入參數屬性名爲arg，可以獲得傳入切點的參數內容，也可通過@annotation獲得切點的註解內容
    @Before("pointcut() && args(arg)")
    public void beforeWithParam(String arg) {
        System.out.println("BeforeWithParam." + arg);
    }

    @Before("pointcut() && @annotation(moocMethod)")
    public void beforeWithAnnotaion(MoocMethod moocMethod) {
        System.out.println("BeforeWithAnnotation." + moocMethod.value());
    }
    //可以獲得切點的返回值
    @AfterReturning(pointcut="bizPointcut()", returning="returnValue")
    public void afterReturning(Object returnValue) {
        System.out.println("AfterReturning : " + returnValue);
    }
    //可以獲得切點拋出的異常信息
    @AfterThrowing(pointcut="pointcut()", throwing="e")
    public void afterThrowing(RuntimeException e) {
        System.out.println("AfterThrowing : " + e.getMessage());
    }

    @After("pointcut()")
    public void after() {
        System.out.println("After.");
    }
//around 第一個參數必須爲ProceedingJoinPoint
    @Around("pointcut()")
    public Object around(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("Around 1.");
        Object obj = pjp.proceed();
        System.out.println("Around 2.");
        System.out.println("Around : " + obj);
        return obj;
    }

}

Around 1.
Before.
BeforeWithAnnotation.MoocBiz save with MoocMethod.
BeforeWithParam.This is test.
MoocBiz save : This is test.
Around 2.
Around :  Save success!
After.
AfterReturning :  Save success!

  <context:component-scan base-package="com.imooc.aop.aspectj"/>
        <aop:aspectj-autoproxy></aop:aspectj-autoproxy>