java - hibernate什么时候加载映射关系

Question

我正在创建一个 Spring Boot 应用程序，并使用它的 JpaRepository 接口(interface)构建来存储我的实体。我有以下两个实体(为了可读性删除了 getter 和 setter):

个人资料实体

@Entity
public class Profile {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    @OneToMany(mappedBy = "profileOne", orphanRemoval = true)
    private List<Match> matchOnes;

    @OneToMany(mappedBy = "profileTwo", orphanRemoval = true)
    private List<Match> matchTwos;
}

匹配实体

@Entity
@Table(uniqueConstraints={
    @UniqueConstraint(columnNames = { "profileOne_id", "profileTwo_id" })
}) 
public class Match {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    @ManyToOne
    @JoinColumn(name = "profileOne_id")
    private Profile profileOne;

    @ManyToOne
    @JoinColumn(name = "profileTwo_id")
    private Profile profileTwo;
}

为了理解 JpaRepository 行为，我编写了以下单元测试。

@RunWith(SpringRunner.class)
@DataJpaTest
public class IProfileDaoTest {

    @Autowired
    private IProfileDao profileDao; //This class extends JpaRepository<Profile, long>

    @Autowired
    private IMatchDao matchDao; //This class extends JpaRepository<Match, long>

    @Test
    public void saveProfileTest() throws Exception {

    @Test
    public void profileMatchRelationTest() throws Exception {
        //Test if matches stored by the IMatchDao are retrievable from the IProfileDao
        Profile profileOne = new Profile("Bob"),
            profileTwo = new Profile("Alex");
        profileDao.saveAndFlush(profileOne);
        profileDao.saveAndFlush(profileTwo);
        matchDao.saveAndFlush(new Match(profileOne, profileTwo));
        profileOne = profileDao.getOne(profileOne.getId());
        Assert.assertEquals("Match not retrievable by profile.", 1, profileOne.getMatchOnes().size());
    }
}

现在我预计匹配项会出现在个人资料实体中，但事实并非如此。我还尝试将 CascadeType.ALL 添加到匹配实体中的 @ManyToOne 注释，并将 FetchType.EAGER 添加到 @OneToMany 配置文件实体中的注释。

是否可以通过请求 profileDao 中的配置文件来获取用 matchDao 保存的比赛？或者我应该找到具有单独功能的配置文件的匹配项？

Answer 1

出于性能(可能还有其他)原因，Spring Data 存储库不会立即写入数据库。在测试中，如果您需要测试查询方法，则需要使用 @DataJpaTest 提供的 TestEntityManager (它只是存储库在后台使用的实体管理器，但有一些方便的测试方法)。

更新 1:匹配项不会添加到个人资料中。为了确保关系是双向的，匹配项应该具有配置文件，但配置文件也应该具有匹配项。

试试这个:

@RunWith(SpringRunner.class)
@DataJpaTest
public class IProfileDaoTest {

    @Autowired
    private IProfileDao profileDao; //This class extends JpaRepository<Profile, long>

    @Autowired
    private IMatchDao matchDao; //This class extends JpaRepository<Match, long>

    @Autowired
    private TestEntityManager testEntityManager;

    @Test
    public void saveProfileTest() throws Exception {

    @Test
    public void profileMatchRelationTest() throws Exception {
        //Test if matches stored by the IMatchDao are retrievable from the IProfileDao
        Profile profileOne = new Profile("Bob"),
            profileTwo = new Profile("Alex");

        //Persist the profiles so they exist when they are added to the match
        entityManager.persistAndFlush(profileOne);
        entityManager.persistAndFlush(profileTwo);

        //Create and persist the match with two profiles
        Match yourMatch = entityManager.persistFlushFind(new Match(profileOne, profileTwo));

        //Add the match to both profiles and persist them again.
        profileOne.matchOnes.add(yourMatch);
        entityManager.persistAndFlush(profileOne);
        profileTwo.matchTwos.add(yourMatch);
        entityManager.persistAndFlush(profileTwo);

        profileOne = profileDao.getOne(profileOne.getId());
        Assert.assertEquals("Match not retrievable by profile.", 1, profileOne.getMatchOnes().size());
    }
}