API Rest - OneToMany / ManyTone 与 JPA 和 Hibernate

Question

我与这两个实体有如下关系

· 运动有很多运动翻译

·SportTranslation 属于 Sport

· 是双向的

当我尝试从 SportTranslation 访问到 Sport 时，我收到以下错误。

java.lang.StackOverflowError: null
    at java.util.AbstractCollection.toString(AbstractCollection.java:454) ~[na:1.8.0_191]
    at org.hibernate.collection.internal.PersistentBag.toString(PersistentBag.java:510) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]

错误不明确，表不为空。

·我有经典的以下Spring MVC架构

控制器

@RestController
@RequestMapping("/api/public/sports")
public class SportController implements ISportsController {

    Logger logger = LoggerFactory.getLogger(SportController.class);


    @Autowired
    private SportsMethods sportMethods;

    @GetMapping(value = "/")
    @Override
    public ResponseEntity<List<SportDTO>> getSports(Pageable pageable) {
        logger.info("--- Retrieve name of class --- : " +this.getClass().getSimpleName() + " --- Method name --- : " + new Object(){}.getClass().getEnclosingMethod().getName());

        List<SportDTO> sportsMethodsList = sportMethods.retreiveListSports(pageable);

        logger.info("--- Final list ---" + sportsMethodsList);
        return new ResponseEntity<List<SportDTO>>(sportsMethodsList,
                (sportsMethodsList == null || sportsMethodsList.isEmpty()) ? HttpStatus.NO_CONTENT : HttpStatus.OK);
    }

}

· 类方法

@组件 公共类 SportsMethods {

@Autowired
private SportService sportService;

public List<SportDTO> retreiveListSports(Pageable pageable) {

    List<SportDTO> sportList = sportService.retreiveListSports();

    return sportList;
}

}

· 服务

@Component
public class SportService implements ISportService {

    Logger logger = LoggerFactory.getLogger(SportService.class);

    @Autowired
    private SportRepository sportRepository;

    @Autowired
    private SportAdapter sportAdapter;

    @Override
    public List<SportDTO> retreiveListSports() {

        List<Sport> sportList = sportRepository.findAll();

        logger.info("--- Retrieve List Of Sports---"+sportList);

        List<SportDTO > sportListDTO = sportAdapter.convertListSport2ListSportDTO(sportList);

        logger.info("--- Retrieve a List Of SportsDTO" +sportListDTO);

        return sportListDTO;

    }

}

· 两个适配器（SportAdatper , SportTranslationAdapter）

·运动适配器

@组件 公共类 SportAdapter {

Logger logger = LoggerFactory.getLogger(SportAdapter.class);

@Autowired
private SportTranslationAdapter sportTranslationAdapter;

public List<SportDTO> convertListSport2ListSportDTO(List<Sport> sportList) {

    logger.info("--- Sport List adapter" + sportList);

    List<SportDTO> sportDTOList = new ArrayList<SportDTO>();

    for (Sport sport : sportList) {

        SportDTO sportDTO = new SportDTO();
        sportDTO.setId(sport.getId());
        sportDTO.setClave(sport.getClave());
        sportDTO.setSportTranslationDTO(sportTranslationAdapter.convertSportTranslation2SportTranslationDTO(sport.getSportTranslation()));
        sportDTOList.add(sportDTO);
    }


    logger.info("--- Sport DTO List adapter" + sportDTOList);

    return sportDTOList;
}

·SportTranslationAdapter

@Component
public class SportTranslationAdapter {

    Logger logger = LoggerFactory.getLogger(SportTranslationAdapter.class);

    public List<SportTranslationDTO> convertSportTranslation2SportTranslationDTO(List<SportTranslation> list) {
        List<SportTranslationDTO> sportTranslationDTOList = new ArrayList<SportTranslationDTO>();
        for (SportTranslation sportTranslation : list) {
            SportTranslationDTO sportTranslationDTO = new SportTranslationDTO();            
                        sportTranslationDTO.setSportId(sportTranslation.getSport().getId());
            sportTranslationDTO.setName(sportTranslation.getName());
            sportTranslationDTOList.add(sportTranslationDTO);

        }
        return sportTranslationDTOList;
    }

}

· Entity Sport 和 SportTranslation

·运动

@Entity
@Table(name = "sport")
public class Sport implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "sport_id")
    private Long id;

    @Column(name = "clave")
    private String clave;

    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
    @JoinColumn(name = "sport_id")
    private List<SportTranslation> sportTranslation;

·体育翻译

@Entity
@Table(name = "sportstranslation")
public class SportTranslation implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "sportstranslation_id")
    private long idSportTranslation;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "sport_id", nullable = true)
    private Sport sport;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "language_id", nullable = true)
    private Language languageId;

    @Column(name = "name")
    private String name;

· 语言工作正常，但这不是运动的问题。

有人可以帮助我吗？

Answer 1

我建议您的实体关联更新如下：

@Entity
@Table(name = "sport")
public class Sport implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "sport_id")
private Long id;

@Column(name = "clave")
private String clave;

@OneToMany(mappedBy = "sport", cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
private List<SportTranslation> sportTranslation;

@Entity
@Table(name = "sportstranslation")
public class SportTranslation implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "sportstranslation_id")
private long idSportTranslation;

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "sport_id", nullable = true)
private Sport sport;

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "language_id", nullable = true)
private Language languageId;

@Column(name = "name")
private String name;

另外，使用@Transactional 注释您获取数据的服务方法。