Question

当我试图坚持它时，我收到一条错误，说我的实体已经分离了。调试时我可以看到我尝试保存的对象有一个ID。我猜这可能与我在JPA中的注释有关但我无法弄清楚这个问题的原因是什么。

带有导致错误的方法的类（doStuff（）的最后一行负责）：

@RestController
@RequestMapping("/test")
public class ConcreteMyController implements MyController {

    private final CategoryService categoryService;
    private final OrmFactory ormFactory;
    private final SongService songService;
    private final CategoryForSongService categoryForSongService;

    @Autowired
    public ConcreteMyController(CategoryService categoryService, OrmFactory ormFactory, SongService songService, CategoryForSongService categoryForSongService) {
        this.categoryService = categoryService;
        this.ormFactory = ormFactory;
        this.songService = songService;
        this.categoryForSongService = categoryForSongService;
    }

    @RequestMapping(method = RequestMethod.GET)
    @ResponseStatus(value = HttpStatus.OK)
    @Override
    public void doStuff() {
        String title = "BestSongInTheWorld";
        String popCategoryName = "pop";
        String rockCategoryName = "rock";
        String jazzCategoryName = "jazz";

        Song song = this.ormFactory.createSong(title, "3:14");
        this.songService.save(song);
        Set<Category> categories = Sets.newHashSet(new Category(popCategoryName), new Category(rockCategoryName), new Category(jazzCategoryName));
        this.categoryService.save(categories);

        Song retrievedSong = songService.get(title);
        Set<Category> retrievedCategories = categoryService.get(Sets.newHashSet(popCategoryName, rockCategoryName));

        CategoryForSong categoryForSong = new CategoryForSong(retrievedSong.getTitle(), retrievedCategories);
        this.categoryForSongService.save(categoryForSong);

    }
}

实体：

@Entity
@Table
public class Category implements Serializable {
    private static final long serialVersionUID = 1L;
    @Column(name = "name")
    private String name;
    @Id
    @GeneratedValue
    private Long id;
}

@Entity
@Table
public class Song implements Serializable {
    private static final long serialVersionUID = 1L;
    @Column(name = "duration")
    private String duration;
    @Column(name = "title")
    private String title;
    @Id
    @GeneratedValue
    private Long id;
}

@Entity
@Table
public class CategoryForSong implements Serializable {
    private static final long serialVersionUID = 1L;
    @JoinColumn(name = "categories")
    @ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    private Set<Category> categories;
    @Column(name = "songTitle")
    private String songTitle;

    @Id
    @GeneratedValue
    private Long id;
}

Getters，setters，equals等已被省略。 CategoryForSong包含带有songTitle而不是实际Song的字符串的原因只是我试图隔离问题。这似乎没有帮助。

我的服务不是很有趣，所以我会在这里添加一首歌来展示结构：

@Service
public class ConcreteSongService implements SongService {

    @Autowired
    private SongRepository songRepository;


    @Transactional
    @Override
    public void save(Song song) {
        songRepository.save(song);
    }

    @Transactional
    @Override
    public Song get(String title) {
        return songRepository.getByTitle(Sets.newHashSet(title)).stream().findFirst().get();

    }
}

存储库就像这样简单：

public interface SongRepository extends CrudRepository<Song, Long> {

    Set<Song> getByTitle(Set<String> titles);
}

例外情况如下：

org.hibernate.PersistentObjectException: detached entity passed to persist: proofofconcept.springmvc.model.orm.Category

非常感谢帮助。

“分离的实体传递给持久化：”当实体未分离时

0 个答案: