在多对一中使用 Spring Data JPA 保持错误关系答案

【问题标题】：Error relationship persistence using Spring Data JPA in a many to one在多对一中使用 Spring Data JPA 保持错误关系
【发布时间】：2021-08-08 06:47:32
【问题描述】：

我有以下代码用于使用 Spring JPA 进行多对多或多对一关系持久性。

这是我的存储库测试https://github.com/Truebu/testJpa.git

这个类有三个一对多的关系，但没有一个很好用

@Entity(name = "routine_assignament")
@Table(name = "routine_assignament")
public class RoutineAssignament {

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "id", updatable = false)
    private Long id;

    @Column(name = "date_start",nullable = true,columnDefinition = "DATE")
    private Date date_start = new Date();

    @Column(name = "date_end",nullable = true,columnDefinition = "DATE")
    private Date date_end;

    @ManyToOne
    @JoinColumn(name = "id_user")
    private User user;

    @ManyToOne
    @JoinColumn(name = "id_routine")
    private Routine routine;

    @OneToMany(mappedBy = "routine_assignament")
    private Set<Score> scores = new HashSet<>();

    @OneToMany(mappedBy = "routine_assignament")
    private Set<Statistic> statistics = new HashSet<>();

    @OneToMany(mappedBy = "routine_assignament")
    private Set<KeepRoutine> keepRoutines = new HashSet<>();

其他类

@Entity(name = "score")
@Table(name = "score")
public class Score {

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "id", updatable = false)
    private Long id;

    @Column(name = "commentary",nullable = false,columnDefinition = "TEXT", unique = true)
    private String commentary;

    @Column(name = "assessment",nullable = false,columnDefinition = "INT", unique = true)
    private String assessment;

    @ManyToOne
    @JoinColumn(name = "id_routine_assignament")
    private RoutineAssignament routineAssignament;

}

@Entity(name = "statistic")
@Table(name = "statistic")
public class Statistic {

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "id", updatable = false)
    private Long id;

    @Column(name = "time",nullable = false,columnDefinition = "TEXT", unique = true)
    private String time;

    @ManyToOne
    @JoinColumn(name = "id_routine_assignament")
    private RoutineAssignament routineAssignament;

}

和

@Entity(name = "keep_routine")
@Table(name = "keep_routine")
public class KeepRoutine {

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "id", updatable = false)
    private Long id;

    @ManyToOne
    @JoinColumn(name = "id_routine_assignament")
    private RoutineAssignament routineAssignament;

}

实体关系图是这样的：

我的错误是它没有正确检测这些关系。

当我运行它时，它会生成：

Failed to initialize JPA EntityManagerFactory: mappedBy reference an unknown target entity property: com.example.demo.model.entities.KeepRoutine.routine_assignament in com.example.demo.model.entities.RoutineAssignament.keepRoutines

这个错误在所有三个类（KeepRoutine、Statistic 和 Score）中都出现了，我不知道为什么

【问题讨论】：

标签： java mysql spring-boot jpa spring-data

【解决方案1】：

您的OneToMany 映射不合适。您需要使用routineAssignament 属性名而不是表名routine_assignament，如下所示。此属性名称在ManyToOne 关系中定义。

    @OneToMany(mappedBy = "routineAssignament")
    private Set<Score> scores = new HashSet<>();

    @OneToMany(mappedBy = "routineAssignament")
    private Set<Statistic> statistics = new HashSet<>();

    @OneToMany(mappedBy = "routineAssignament")
    private Set<KeepRoutine> keepRoutines = new HashSet<>();

【讨论】：