java - Hibernate @ManyToMany -- 未填充连接表

Question

我正在尝试实现 @ManyToMany 关系，但我的联接表尚未填充。我的应用程序将一堆竞争对象建模为竞争对手对象。有一群竞争对手。在该组中，每个参赛者与其他参赛者进行匹配以形成竞赛。所以每个Competition都可以有一个Competitor对象的列表。每个参赛者可以参加多个比赛。

实体对象

竞争是这样的:

@Entity
@Table(name = "competition")
public class Competition implements java.io.Serializable {

    @Id
    @GeneratedValue
    private int competitionId;

    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "competition_competitors", joinColumns = @JoinColumn(name = "competitionId"), inverseJoinColumns = @JoinColumn(name = "competitorId"))
    private Set<Competitor> competitors = new TreeSet<Competitor>();

            . . .

我的竞争对手对象看起来像这样:

@Entity
@Table(name = "competitor")
public class Competitor implements Comparable<Competitor>, java.io.Serializable {

    @Id
    @GeneratedValue
    private int competitorId;

    @ManyToMany(mappedBy = "competitors", cascade = CascadeType.ALL)
    private Set<Competition> competitions = new TreeSet<Competition>();

            . . .

竞赛服务方式

@Override
@Transactional(readOnly = false)
public Competition createCompetition(League league, Competitor competitor1, Competitor competitor2) {
    Competition competition = getCompetitionDAO().create(league);
    competition.add(competitor1);
    competition.add(competitor2);
    this.competitionDao.saveOrUpdate(competition);
    return competition;
}

CompetitionDAO方法

@Override
@Transactional(readOnly = false)
public void saveOrUpdate(Competition competition) {
    if (competition != null) {
        Session session = getCurrentSession();
        try {
            session.saveOrUpdate(competition);
        } catch (Exception exception) {
            throw new AppException(exception);
        }
    }
}

应用程序代码

这段代码应该创建一个竞争并持续下去。它曾经这样做过，但在某个地方我破坏了它，它不再将任何内容保存到连接表 {competition_competitors} 中。

@Transactional(readOnly = false)
private void createLeague(LeagueData leagueData) {

    User user = createAccount( ... );
    League league = createLeague(user, leagueData.getLeagueName());

    for (int index = 0; index < leagueData.getCompetitorNames().length; index++) {
        Competitor competitor = this.serviceProvider.getCompetitorService().find(league, leagueData.getCompetitorNames()[index]);
        if (competitor == null) {
            competitor = createCompetitor(league, leagueData.getCompetitorNames()[index], leagueData.getCompetitorDescription()[index]);
        }
        this.serviceProvider.getCompetitionService().createCompetition(league, competitor);
    }
}

问题:对于应用运行时为何未填充联接表有什么想法吗？应用代码运行时没有错误。我不明白为什么单元测试可以工作并正确填充连接表，但类似的应用程序代码却不能。

Answer 1

如果您看不到 MySQL Workbench 中出现的值，但您的单元测试通过了，这是因为 Spring 在单元测试完成后自动回滚事务。因此，如果您可以在提交事务的那一刻立即刷新 MySQL Workbench，那么您将在事务回滚且值丢失之前看到大约 0.2 毫秒的值。

您的连接表正在工作，否则您的断言将失败。