更改 RequestMapping 方法或 post 添加 Optional in Java 8 from Java 7

Change in RequestMapping method or post addition of Optional in Java 8 from Java 7

我一直在尝试按照教程进行操作,其中他们基本上使用 java 7,目前我正在使用 java 8 环境,所以我想知道 [= =26=]8 版本的代码,我正在尝试处理 - 目前我在使用 Optional 时遇到了很多错误,eclipse 建议修复一些初始错误,但我坚持了一些。

java7代码如下:

@RequestMapping("/reservations")
    public Reservation updateReservation1(ReservationUpdateRequest request) {
        Reservation reservation = reservationRepo.findOne(request.getId());
        reservation.setNumberOfBags((request.getNumOfBags());
        reservation.setCheckedIn(request.getCheckedIn());
        return reservationRepo.save(reservation);
    }

java8 错误

@RequestMapping("/reservations")
    public Optional<Reservation> updateReservation(ReservationUpdateRequest request) {
        Optional<Reservation> reservation = reservationRepo.findById(request.getId());
        reservation.setNumberOfBags((request.getNumOfBags());
        reservation.setCheckedIn(request.getCheckedIn());
        return reservationRepo.save(reservation);
    }

在 java8 中,代码 eclipse ide 在第 3 行给我错误 - 也就是说,当我尝试将值设置为 reservation.setNumberOfBags() 时,它显示 The method setNumberOfBags(int) is undefined for the type Optional<Reservation> - 如果有人可以提供帮助?

@RequestMapping("/reservations")
public Optional<Reservation> updateReservation(ReservationUpdateRequest request) {
    Optional<Reservation> reservation = reservationRepo.findById(request.getId());
    if(reservation.isPresent()) {
        Reservation actReservation = reservation.get();
        actReservation .setNumberOfBags((request.getNumOfBags());
        actReservation .setCheckedIn(request.getCheckedIn());
        return reservationRepo.save(actReservation );
    }
    else {
        return Optional.empty();
    }
}

你应该 return Reservation 而不是 Optional<Reservation> (我猜你正在使用 Spring 数据,请参阅保存方法)。

如果您想在未找到预订时抛出异常,请使用:

public Reservation updateReservation(ReservationUpdateRequest request) {
        Reservation reservation = reservationRepo.findById(request.getId())
            .orElseThrow(() -> new EntityNotFoundException("Reservation not found"));
        reservation.setNumberOfBags(request.getNumOfBags());
        reservation.setCheckedIn(request.getCheckedIn());
        return reservationRepo.save(reservation);
    }

如果您想 return 找不到 404 错误代码:

public ResponseEntity<Reservation> updateReservation(ReservationUpdateRequest request) {
     return reservationRepo.findById(request.getId())
         .map(r -> {
              r.setNumberOfBags(request.getNumOfBags());
              r.setCheckedIn(request.getCheckedIn());
              return ResponseEntity.ok().body(reservationRepo.save(r));
          }).orElse(new ResponseEntity<>(HttpStatus.NOT_FOUND));
    }

而且 RequestMapping 很奇怪,您应该在 URL 中使用带有 id 的 PUT 而不是请求正文。

@PutMapping("/reservations/{id}")
public ResponseEntity<Reservation> updateReservation(@PathParam("id") Long id, ReservationUpdateRequest request) {
     return reservationRepo.findById(id)
         .map(r -> {
             r.setNumberOfBags(request.getNumOfBags());
             r.setCheckedIn(request.getCheckedIn());
             return ResponseEntity.ok().body(reservationRepo.save(r));
         }).orElse(new ResponseEntity<>(HttpStatus.NOT_FOUND));
}