java-Spring-Data-Jpa保存：保存为null的相关实体不是

我有实体时间表：

@Entity @Table(name = TableUtils.TIMETABLE)public class Timetable {

private static final long serialVersionUID = -1307879048598194633L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = ColumnUtils.ID)
private long id;

@OneToMany(mappedBy = "timetable", cascade = {CascadeType.REMOVE, CascadeType.PERSIST})
private List<TimetableCell> timetableCells;

public List<TimetableCell> getTimetableCells() {
    return timetableCells;
}

public void setTimetableCells(List<TimetableCell> timetableCells) {
    this.timetableCells = timetableCells;
}
}

和一个实体的时间表单元：

@Entity
@Table(name = TableUtils.TIMETABLE_CELL)
public class TimetableCell extends AbstractElement {

private static final long serialVersionUID = -8083688091896353882L;

@ManyToOne(cascade = CascadeType.PERSIST)
@JoinColumn(name = ColumnUtils.WEEK_DAY_ID, nullable = false)
private WeekDay weekDay;

@ManyToOne(cascade = CascadeType.PERSIST)
@JoinColumn(name = ColumnUtils.LESSON_HOUR_ID, nullable = false)
private LessonHour lessonHour;

@ManyToOne(cascade = CascadeType.PERSIST)
@JoinColumn(name = ColumnUtils.TIMETABLE_ID, nullable = false)
private Timetable timetable;

...
}

首先,我使用weekDay和LessonHours创建时间表单元格.在将此列表设置为时间表并尝试保存之后.但是所有时间表单元格都使用空的weekDay和空的LessonHour保存.
我调试了在保存之前,还设置了所有字段.

timetableRepository.save(timetable);

调试结果显示如下

解决方法:

1)timetableCells仅用以下级联类型标记：

@OneToMany(mappedBy = "timetable", cascade = {CascadeType.REMOVE, CascadeType.PERSIST})

2)周和小时部门只有以下几点：

@ManyToOne(cascade = CascadeType.PERSIST)

3)如果您在此处传递时间表以保存方法,并且该方法之前一直存在：

timetableRepository.save(timetable);

Spring Data JPA不会调用持久化,而是合并.

为什么级联不起作用可能是这种情况.如果将其添加到配置中,则可能会得到所需的内容：

cascade = {CascadeType.REMOVE, CascadeType.PERSIST, CascadeType.MERGE})

标签：spring-data-jpa,hibernate,java
来源： https://codeday.me/bug/20191210/2104435.html