Question

以下是两个实体类。子类具有单向@ManyToOne映射。

PlantDetails：

@Entity
@Table(name = "PLANT_DETAILS", uniqueConstraints={ @UniqueConstraint(columnNames = {"PLANT"})})
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler", "ignoreUnknown = true"})
public class PlantDetails implements Serializable {
        private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name = "PLANT_ID")
    private Long plantId;
    @Column(name = "PLANT")
    private String plant;
    @Column(name = "PLANT_DETAILS")
    private String plant_Details;
    @Column(name = "LOCATION")
    private String location;
    @JsonCreator
    public PlantDetails(  @JsonProperty("plantId") Long plantId, 
                          @JsonProperty("plant") String plant,
                          @JsonProperty("plant_Details") String plant_Details,
                          @JsonProperty("location") String location )

                  {
        this.plantId = plantId;
        this.plant = plant;
        this.plant_Details = plant_Details;
        this.location = location;
    }

LineDetails：

@Entity
    @Table(name = "LINE_DETAILS", uniqueConstraints={ @UniqueConstraint(columnNames = { "PLANT", "LINE_NAME" })})
    @JsonIgnoreProperties({"hibernateLazyInitializer", "handler", "ignoreUnknown = true"})
        public class LineDetails implements Serializable {
                private static final long serialVersionUID = 1L;

        @Id
        @GeneratedValue(strategy=GenerationType.IDENTITY)
        @Column(name = "LINE_ID")
        private Long lineId;

        @ManyToOne(cascade=CascadeType.ALL)
        @JoinColumn(name="PLANT", referencedColumnName = "PLANT")
        private PlantDetails plantDetails;

        @Column(name = "LINE_NAME")
        private String lineName;
        @Column(name = "LINE_DESCRIPTION")
        private String lineDescription;

        @JsonCreator
        public LineDetails( @JsonProperty("lineId") Long lineId, 
                            @JsonProperty("lineName") String lineName,
                            @JsonProperty("lineDescription") String lineDescription) {

            this.lineId = lineId;
            this.lineName = lineName;
            this.lineDescription = lineDescription;
        }

我正在尝试进行基本的CRUD操作。以下代码更新子表。我可以使用setter更新列。但我无法更新@JoinColumn字段“plant”，因为我在实体类的@jsoncreator构造函数中没有它。如何更新该字段？

在创建/插入记录时，我通过从plantdetails实体ID列获取其值而不是@JoinColumn来设置@jsoncreator字段“plant”。

在DAOimpl

    @Override
        public void updateLineDetails(LineDetails lineDetails) {

            Session session = this.sessionFactory.getCurrentSession();

            LineDetails existinglineDetails = (LineDetails) session.get(LineDetails.class, 
            lineDetails.getLineId());
            existinglineDetails.setLineName(lineDetails.getLineName());
            existinglineDetails.setLineDescription(lineDetails.getLineDescription());

            session.update(existinglineDetails);
    }

Answer 1

您必须以某种方式传递此字段所代表的值：

@Column(name = "PLANT")
private String plant;

我通常不会通过实体结构本身传递数据。我会创建额外的LineDetailsInfo类，它将保存普通字段中的所有信息。

public class LineDetailsInfo{

        @JsonCreator
        public LineDetails( @JsonProperty("lineId") Long lineId, 
                            @JsonProperty("lineName") String lineName,
                            @JsonProperty("lineDescription") String lineDescription,
                            @JsonProperty("plant") String plant) {
            this.plant = plant;
            this.lineId = lineId;
            this.lineName = lineName;
            this.lineDescription = lineDescription;
        }
}

然后，您需要查询该特定PlantDetails实体并相应地更新父实体：

    @Override
    public void updateLineDetails(LineDetailsInfo lineDetailsInfo) {
        Session session = this.sessionFactory.getCurrentSession();

        PlantDetails pd = (PlantDetails)session.createQuery("from PlantDetails where plant = :plant")
                                 .setString("plant", lineDetailsInfo.getPlant()).uniqueResult();
        LineDetails existinglineDetails = (LineDetails) session.get(LineDetails.class, 
        lineDetailsInfo.getLineId());
        existinglineDetails.setLineName(lineDetailsInfo.getLineName());
        existinglineDetails.setPlantDetails(pd);

       existinglineDetails.setLineDescription(lineDetailsInfo.getLineDescription())

        session.update(existinglineDetails);
    }

更新单向多对一连接列值

1 个答案: