Spring中@ManyToOne与@JoinColumn无法加载OsDto关联数据问题

相关代码 #

Device实体类 #

@Entity
@Getter
@Setter
public class Device {

    @Id
    @org.springframework.data.annotation.Id
    @UuidGenerator
    private UUID id;

    /**
     * The hardware associated with the device.
     *
     * @see GenericHardwareData for more info
     */
    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "hardware")
    private GenericHardwareData hardware;

    /**
     * The storage capacity of the device.
     */
    private int storage;

    /**
     * The operating system of the device.
     */
    @ManyToOne
    @JoinColumn(name = "operation_system")
    private OsDto operationSystem;

    private String name;

}

OsDto实体类 #

@Entity
@Getter
@Setter
public class OsDto {

    @Id
    @org.springframework.data.annotation.Id
    @UuidGenerator
    private UUID id;

    @Column(unique = true)
    private String name;

}

HardwareController控制器代码 #

@Slf4j
@RestController
@RequestMapping("/hardware")
public class HardwareController {


    private final HardwareRepository hardwareRepository;
    private final HardwareService hardwareService;


    @Autowired
    public HardwareController(HardwareRepository hardwareRepository, HardwareService hardwareService) {
        this.hardwareRepository = hardwareRepository;
        this.hardwareService = hardwareService;
    }


    @GetMapping
    @Secured({"ADMIN", "VIEW"})
    public ResponseEntity<?> getHardware() {
        return ResponseEntity.ok(this.hardwareRepository.findAll());
    }

    @GetMapping("/find")
    @Secured({"ADMIN", "VIEW"})
    public ResponseEntity<?> getHardwareByQrCode(@RequestParam("qrcode") String qrCode) {
        try {
            int qr = Integer.parseInt(qrCode);
            return ResponseEntity.of(this.hardwareRepository.findByQrCode(qr));
        } catch (NumberFormatException e) {
            return ResponseEntity.badRequest().body("{\"error\": \"qr code can't be parsed to integer\"}");
        }
    }

    @GetMapping("/device")
    @Secured({"ADMIN", "VIEW"})
    public ResponseEntity<?> getComputerByQrCode(@RequestParam("qrcode") String qrCode, @RequestParam("type") String rawHardwareType) {

        try {
            HardwareType hardwareType = HardwareType.valueOf(rawHardwareType);

            switch (hardwareType) {
                case COMPUTER -> {
                    return this.hardwareService.getComputerFromQrCode(qrCode);
                }
                case DOCKING_STATION -> {
                    return this.hardwareService.getDockingStationByQrCode(qrCode);
                }
                case MOBILE -> {
                    return this.hardwareService.getMobileFromQrCode(qrCode);
                }
                case MONITOR -> {
                    return this.hardwareService.getMonitorByQrCode(qrCode);
                }
                case PRINTER -> {
                    return this.hardwareService.getPrinterByQrCode(qrCode);
                }
            }

        } catch (IllegalArgumentException e) {
            return ResponseEntity.badRequest().body("{\"error\": \"hardware type couldn't be serialized\"}");
        }

        return ResponseEntity.notFound().build();
    }

    @GetMapping("/find/{type}")
    @Secured({"ADMIN", "VIEW"})
    public ResponseEntity<?> getHardwareByType(@PathVariable String type) {

        try {
            return ResponseEntity.ok(this.hardwareRepository.findAllByHardwareType(HardwareType.valueOf(type.toUpperCase())));
        } catch (IllegalArgumentException e) {
            return new ResponseEntity<>(e.getMessage(), HttpStatus.BAD_REQUEST);
        }

    }

}

当前问题与排查情况 #

• 前端Angular应用的Chrome日志显示，接口返回的Device对象中operationSystem字段为null
• 已确认数据库中：
  • device表的operation_system字段存储了正确的关联UUID
  • os_dto表中存在对应UUID的OsDto数据
• 尝试给Device类中operationSystem字段的@ManyToOne注解添加FetchType.EAGER属性，问题未解决，该字段仍为null

内容的提问来源于stack exchange，提问作者DasShorty