Question

val conf = new SparkConf().setMaster("local[2]").setAppName("NetworkWordCount")
val streamingContext = new StreamingContext(conf, Seconds(1))

@Entity
@Table(name="Visit")
public class Visit {
    @Id
    @XmlTransient
    @JsonIgnore
    @SequenceGenerator(name = "v_id_seq", sequenceName = "v_id_seq", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "v_id_seq")
    @Column(name = "id")
    private Long id;

    @OneToMany(mappedBy = "Visit",cascade = CascadeType.PERSIST,orphanRemoval = true,fetch=FetchType.LAZY)
    private List<directions> directions;

    @OneToMany(mappedBy = "Visit",cascade = CascadeType.PERSIST,orphanRemoval = true,fetch=FetchType.LAZY)
    private List<Test> Test;

@Entity
@Table(name="test")
public class Test {
    @Id
    @XmlTransient
    @JsonIgnore
    @SequenceGenerator(name = "t_id_seq", sequenceName = "t_id_seq", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "t_id_seq")
    @Column(name = "id")
    private Long id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JsonBackReference
    @JoinColumn(name = "vid", updatable = false, insertable = true,referencedColumnName = "id")
    private Visit visit;

你好，我是新来的冬眠我正在尝试映射OneToMany Visit-> Test and Visit-> direction但出现错误 @Entity @Table(name="direction") public class directions { @Id @XmlTransient @JsonIgnore @SequenceGenerator(name = "d_id_seq", sequenceName = "d_id_seq", allocationSize = 1) @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "d_id_seq") @Column(name = "id") private Long id; @ManyToOne(fetch = FetchType.LAZY) @JsonBackReference @JoinColumn(name = "vid", updatable = false, insertable = true,referencedColumnName = "id") private Visit Visit;

一次访问可以有多个方向和测试我该如何实现呢？

请帮助我！

Answer 1

mappedBy批注中的@OneToMany字段的值引用Java实例变量名称，并且区分大小写。您将其设置为Visit，但是在directions和test类中，变量名称为visit。

解决方案是将属性mappedBy从Visit更改为visit（小写V）：

@OneToMany(mappedBy = "visit",cascade = CascadeType.PERSIST,orphanRemoval = true,fetch=FetchType.LAZY)
private List<directions> directions;

@OneToMany(mappedBy = "visit",cascade = CascadeType.PERSIST,orphanRemoval = true,fetch=FetchType.LAZY)
private List<Test> Test;

休眠多个表的一对多映射

1 个答案: