java - Ebean/Play Framework 关系未更新

Question

我正在使用带有 Ebean 和 Java 的游戏框架 2.3.3。 我有以下模型(我实现了 getter 和 setter):

@Entity
public class Follow {

  @ManyToOne
  private User follower;

  @ManyToOne
  private User followed;
}

和

@Entity
public class User {

  @Id
  @GeneratedValue
  private long id;

  @OneToMany(mappedBy = "followed")
  private Set<Follow> followers;

  @OneToMany(mappedBy = "follower")
  private Set<Follow> following;

  public void addFollowing(Follow f) { following.add(f); }
  public void addFollower(Follow f) { followers.add(f); }
}

为了测试这种关系，我有:

@Test
public void userFollowTest() {
    User a = new User();
    User b = new User();
    Follow follow = new Follow(a, b); // a follows b
    a.addFollowing(follow);
    b.addFollower(follow);

    Ebean.beginTransaction();
    Ebean.save(a);
    Ebean.save(b);
    Ebean.save(follow);
    Ebean.commitTransaction();

    Assert.assertEquals("Number of users", 2, User.find.all().size());
    Assert.assertEquals("Number of following of user A", 1, User.find.byId(1L).getFollowing().size());
    Assert.assertEquals("Number of followers of user B", 1, User.find.byId(2L).getFollowers().size());
    Assert.assertEquals("Number of follows", 1, Follow.find.all().size());
}

但这行得通:

Assert.assertEquals("Number of users", 2, User.find.all().size());
Assert.assertEquals("Number of following of user A", 1, a.getFollowing().size());
Assert.assertEquals("Number of followers of user B", 1, b.getFollowers().size());
Assert.assertEquals("Number of follows", 1, Follow.find.all().size());
Assert.assertTrue("User a is follower and User b is followed", follow.getFollower().getId() == 1 &&
            follow.getFollowed().getId() == 2);

问题是，尽管在数据库中创建了用户和关注者，但第二个和第三个断言失败了(即，用户没有任何关注者)。 我尝试先创建用户，然后再创建关注，但仍然无法正常工作。

Answer 1

已解决。看来解决方法是在实体Follow中创建一个ID字段。 我尝试将这两个字段都作为 ID，但 Ebean 不接受它，所以我最终使用了 long 类型的 ID。