我在 many-to-many 中更新 object 时遇到问题（Spring 启动）

Question

我有两个类（用户和成就）具有 many-to-many 的关系。当我创建并建立它们之间的关系，然后我想使用 put 方法更新任何 objects 时，"user_achievement_open" table 中的关系被删除。我的错误在哪里？

整体意在将一组任务分配给共同的标题"Achievement"。然后用户可以选择他要完成的成就。不同的用户可以执行相同的成就。一个用户可以同时执行多个不同的成就。

@Entity
@Table(name = "user")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "user_id")
    private int userId;

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

    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "user_data_id")
    private UserData userDataId;

    @OneToMany(mappedBy = "userId")
    private List<Realization> realizationList;

    @ManyToMany
    @JoinTable(
            name = "user_achievement_open",
            joinColumns = @JoinColumn(name = "user_id"),
            inverseJoinColumns = @JoinColumn(name = "achievement_id"))
    private List<Achievement> openAchList;

    @ManyToMany
    @JoinTable(
            name = "user_achievement_finished",
            joinColumns = @JoinColumn(name = "user_id"),
            inverseJoinColumns = @JoinColumn(name = "achievement_id"))
    private List<Achievement> finishedAchList;

    public User() {
    }

    public User (String username) {

        this.username = username;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int id) {
        this.userId = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public UserData getUserDataId() {
        return userDataId;
    }

    public void setUserDataId(UserData userData) {
        this.userDataId = userData;
    }

    public void addData(UserData tempUserData) {

        if (userDataId != null) userDataId = null;
        this.userDataId = tempUserData;
    }

    public List<Realization> getRealizationList() {
        return realizationList;
    }

    public void setRealizationList(List<Realization> realizationList) {
        this.realizationList = realizationList;
    }

    public void addRealization(Realization theRealization) {

        if(realizationList == null) realizationList = new ArrayList<>();
        realizationList.add(theRealization);
        theRealization.setUserId(this);
    }

    public List<Achievement> getOpenAchList() {
        return openAchList;
    }

    public void setOpenAchList(List<Achievement> achievementList) {
        this.openAchList = achievementList;
    }

    public void addOpenAch(Achievement theAchievement) {

        if(openAchList == null) openAchList = new ArrayList<>();
        openAchList.add(theAchievement);
    }

    public void removeOpenAch(Achievement theAchievement) {

        if(openAchList.contains(theAchievement)) openAchList.removeIf(Objects::nonNull);
    }

    public List<Achievement> getFinishedAchList() {
        return finishedAchList;
    }

    public void setFinishedAchList(List<Achievement> finishedAchList) {
        this.finishedAchList = finishedAchList;
    }

    public void addFinishedAch(Achievement theAchievement) {

        if(finishedAchList == null) finishedAchList = new ArrayList<>();
        finishedAchList.add(theAchievement);
    }

    public void removeFinishedAch(Achievement theAchievement) {

        if(finishedAchList.contains(theAchievement)) finishedAchList.remove(theAchievement);
    }
}

@Entity
@Table(name = "achievement")
public class Achievement {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "achievement_id")
    private int achievementId;

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

    @OneToMany(mappedBy = "achievementId",
                cascade = CascadeType.ALL)
    private List<Quest> questList;

    @JsonIgnore
    @ManyToMany
    @JoinTable(
            name = "user_achievement_open",
            joinColumns = @JoinColumn(name = "achievement_id"),
            inverseJoinColumns = @JoinColumn(name = "user_id"))
    private List<User> openUserList;

    @ManyToMany
    @JoinTable(
            name = "user_achievement_finished",
            joinColumns = @JoinColumn(name = "achievement_id"),
            inverseJoinColumns = @JoinColumn(name = "user_id"))
    private List<User> finishedUserList;

    public Achievement() {
    }

    public Achievement(String title) {
        this.title = title;
    }

    public int getAchievementId() {
        return achievementId;
    }

    public void setAchievementId(int achievementId) {
        this.achievementId = achievementId;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public List<Quest> getQuestList() {
        return questList;
    }

    public void setQuestList(List<Quest> questList) {
        this.questList = questList;
    }

    public void addQuest(Quest theQuest) {

        if(questList == null) questList = new ArrayList<>();
        questList.add(theQuest);
        theQuest.setAchievementId(this);
    }

    public List<User> getOpenUserList() {
        return openUserList;
    }

    public void setOpenUserList(List<User> userList) {
        this.openUserList = userList;
    }
}

Answer 1

您应该只在一侧设置 @JoinTable，即关系的所有者。另一边是反端，应该只引用它所映射的另一个 class 中的集合，在您的情况下是 @ManyToMany(mappedBy="openUserList") （其他关系也是如此）。

根据 documentation:

If the association is bidirectional, one side has to be the owner and one side has to be the inverse end (ie. it will be ignored when updating the relationship values in the association table)

希望对您有所帮助。

我在 many-to-many 中更新 object 时遇到问题（Spring 启动）

I have problem with update object in many-to-many (Spring Boot)

many-to-many

hibernate

crud

put

spring-boot