spring @AfterReturning返回值问题

@AfterReturning(value = "pointCut()", returning = "obj")
public Object doAfterReturning(JoinPoint joinPoint, Object obj) {
    // 正常情况下，我们想要修改obj，只需要强转为对应的对象，再重新设置值即可，如下
    User user = (User)obj;
    user.setName("test");
    return user;
}

@AfterReturning(value = "pointCut()", returning = "obj")
public Object doAfterReturning(JoinPoint joinPoint, Object obj) {
    // 直接修改了obj的引用地址
    User user = new User();
    obj = user;
    return obj;
}

    @Pointcut(value = "execution(* com.cases.dao.mapper.duty.DutyTableDao.insertBatch(..))")
    public void pointcut() {
        log.info("DutyDeleteInterceptor：pointcut");
    }

@Around(value = "pointcut()")
public void methodAround(ProceedingJoinPoint joinPoint) throws Throwable {
    log.info("DutyDeleteInterceptor：methodAround");
}

    @Around(value = "pointcut()")
    public Object methodAround(ProceedingJoinPoint joinPoint) throws Throwable {
        log.info("DutyDeleteInterceptor：methodAround");
        return joinPoint.proceed();
    }