休眠查询不返回正确的结果

Posted 2023-02-26

【中文标题】休眠查询不返回正确的结果

【英文标题】：Hibernate query not return the correct results

【发布时间】：2015-03-12 17:40:16

【问题描述】：

我正在开发一个带有 hibernate 和 spring 的网络应用程序。我正在为所有配置使用注释。

我的问题是试图选择一个带有两个外键的表。

包含所有的实体是：

@Entity
@Table(name = "WAR_PLAYERS_ATTACKS")
public class WarPlayerAttack implements Serializable 

    private static final long serialVersionUID = 1L;

    @Id
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "WAR_PLAYER")
    private WarPlayer warPlayer;

    @Id
    @ManyToOne
    @JoinColumn(name = "ATTACK")
    private Attack attack;

    @ManyToOne
    @JoinColumn(name = "TYPE_ATTACK")
    private TypeAttack typeAttackInWar;

    public WarPlayerAttack()  

    // getters and setters

实体战争玩家：

@Entity
@Table(name = "WAR_PLAYERS")
public class WarPlayer implements Serializable 

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "ID", nullable = false)
    private int id;

    @ManyToOne
    @JoinColumn(name = "WAR")
    private War war;

    @ManyToOne
    @JoinColumn(name = "PLAYER")
    private Player player;

    @Column(name = "WAR_NUMBER")
    private int warNumber;

    @Column(name = "HAVE_KING")
    private boolean haveKing;

    @Column(name = "HAVE_QUEEN")
    private boolean haveQueen;

    @Column(name = "HAVE_POTIONS")
    private boolean havePotions;

    @OneToMany(mappedBy = "warPlayer", fetch = FetchType.EAGER)
    private List<WarPlayerAttack> attacks;

    public List<WarPlayerAttack> getAttacks() 
        return attacks;
    

    public void setAttacks(List<WarPlayerAttack> attacks) 
        this.attacks = attacks;
    

    private String comment;

    public WarPlayer() 

我的 DAO

    @Override
    public List<WarPlayerAttack> findByIdEnemyAndIdWar(int idEnemy, int idWar) throws DaoException 

        List<WarPlayerAttack> attackss = null;
        List attacks;

        try 
            attackss = getSession()
                .createQuery("from WarPlayerAttack wpa where wpa.attack.enemy.id in :idEnemy and wpa.attack.enemy.war.id in :idWar")
                .setParameter("idEnemy", idEnemy)
                .setParameter("idWar", idWar)
                //.createSQLQuery("select * from WAR_PLAYERS_ATTACKS where ATTACK in (select ID from ATTACKS where ENEMY in (select ID from WAR_ENEMIES where ID = ? and WAR = ?))")
                //.setParameter(0, idEnemy)
                //.setParameter(1, idWar)
                .list();
         catch (Exception e) 
            throw new DaoException(e.getMessage());
        

        return attackss;
    

我的问题是休眠不收集warPlayer。只收集Attack 和TypeAttack。 以 JSON 格式收集的数据示例（出现攻击但未显示 warPlayer）：

[
    "attack":"id":15,"enemy":"id":10,"diffculty":0,"warNumber":2,"stars":1,"strategy":"id":1,"value":"Air","timeRange":"id":1,"value":"6H","typeAttackInWar":"id":3,"value":"Final 1",
    "attack":"id":16,"enemy":"id":10,"diffculty":0,"warNumber":2,"stars":2,"strategy":"id":2,"value":"Ground","timeRange":"id":3,"value":"18H","typeAttackInWar":"id":4,"value":"Final 2"
]

如果我使用 SQL，dao 会返回 Object[]，例如 [[1,1,1],[1,2,1]]

更多信息的表格：

CREATE TABLE WAR_ENEMIES (
    ID INT AUTO_INCREMENT NOT NULL,
    WAR INT NOT NULL,
    WAR_NUMBER INT(2) NOT NULL,
    DIFFCULTY INT(1),

    CONSTRAINT PK_ENEMY PRIMARY KEY (ID),
    CONSTRAINT FK_ENEMY_WAR FOREIGN KEY (WAR) REFERENCES WARS(ID)
);

CREATE TABLE ATTACKS (
    ID INT AUTO_INCREMENT NOT NULL,
    ENEMY INT,
    STARS INT(1) DEFAULT 0,
    STRATEGY INT,
    TIME_RANGE INT,

    CONSTRAINT PK_ATTACK PRIMARY KEY (ID),
    CONSTRAINT FK_ATTACK_ENEMY FOREIGN KEY (ENEMY) REFERENCES WAR_ENEMIES(ID),
    CONSTRAINT FK_ATTACK_STRATEGY FOREIGN KEY (STRATEGY) REFERENCES STRATEGIES(ID),
    CONSTRAINT FK_ATTACK_TIME_RANGE FOREIGN KEY (TIME_RANGE) REFERENCES TIMES_RANGES(ID)
);

CREATE TABLE WAR_PLAYERS (
    ID INT NOT NULL AUTO_INCREMENT,
    WAR INT NOT NULL,
    PLAYER INT NOT NULL,
    WAR_NUMBER INT(2) NOT NULL,
    HAVE_KING TINYINT(1)  NOT NULL DEFAULT 1,
    HAVE_QUEEN TINYINT(1)  NOT NULL DEFAULT 1,
    HAVE_POTIONS TINYINT(1)  NOT NULL DEFAULT 1,
    COMMENT VARCHAR(2500),

    CONSTRAINT PK_PLAYER_IN_WAR PRIMARY KEY (ID),
    CONSTRAINT FK_PLAYER_IN_WAR FOREIGN KEY (WAR) REFERENCES WARS(ID),
    CONSTRAINT FK_PLAYER_IN_WAR_PLAYER FOREIGN KEY (PLAYER) REFERENCES PLAYERS(ID)
);
CREATE TABLE WAR_PLAYERS_ATTACKS (
    WAR_PLAYER INT NOT NULL,
    ATTACK INT NOT NULL,
    TYPE_ATTACK INT NOT NULL,

    CONSTRAINT PK_WAR_PLAYER_ATTACK PRIMARY KEY (WAR_PLAYER, ATTACK),
    CONSTRAINT FK_WAR_PLAYER_ATTACK_WAR_PLAYER 
        FOREIGN KEY (WAR_PLAYER) REFERENCES WAR_PLAYERS(ID),
    CONSTRAINT FK_WAR_PLAYER_ATTACK_ATTACK 
        FOREIGN KEY (ATTACK) REFERENCES ATTACKS(ID),
    CONSTRAINT FK_WAR_PLAYER_ATTACK_TYPE 
        FOREIGN KEY (TYPE_ATTACK) REFERENCES TYPE_ATTACK(ID)

);

我不知道我做错了什么。 （我没有太多时间使用休眠）

在此先致谢并致以最诚挚的问候。

【问题讨论】：

您能否澄清一下，因为目前还不清楚您要问什么。需要注意的一件事是您的 warPlayer 被标记为懒惰。

@M.Deinum 我编辑将warPlayer放在warPlayerAttack之后。

你看过我的评论了吗？ -> 。需要注意的一件事是您的 warPlayer 被标记为惰性。

@M.Deinum 我也试着在这里澄清这个问题。我有一个带有 warPlayers 和 warEnemies 的场景（战争）。 warPlayer 可以对 WarEnemy 进行攻击。我想收集对特定战争敌人的攻击。

@M.Deinum 抱歉，我理解不好。如果我删除 LAZY，我会得到一个 ***Exception

【参考方案1】：

我在使用 EclipseLink 实现时遇到了类似的问题，我只是简单地解决了 prder 中的 callink .size() 方法来初始化惰性收集。见How to load lazy fetched items from Hibernate/JPA in my controller

【讨论】：

我试图按照你的要求做，但是调用 .size() 或 Hibernate.initialize()，我得到了相同的结果，你能用我的代码举个例子吗？我觉得我做错了什么。

您是否尝试过 EAGER FetcType 而不是 LAZY？

是的，我也得到了 ***Exception

在你的 DAO 中调用 .list() 后尝试将 attacks.size() 放入

我这样做了，我得到了相同的结果。我也尝试使用 Hibernate.initialize() 并得到相同的结果。可能会失败，因为warPlayer类有这个？ @OneToMany(mappedBy = "warPlayer", fetch = FetchType.EAGER) private List<WarPlayerAttack> attacks;