Question

我有实体：

第一

@Entity
@Getter
@Setter
@NoArgsConstructor
public class Technic implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    private String gosNumber;

    private String invNumber;

    private String shassisNumber;

    private String engineNumber;

    @Column(length = 100)
    private String yearOfMake;

    @ManyToOne
    private Farm farm;

    @JsonManagedReference
    @ManyToOne
    private TechGroup techGroup;

    @JsonManagedReference
    @ManyToOne
    private TechType techType;

    @JsonManagedReference
    @ManyToOne
    private TechMark techMark;

    @JsonIgnore
    @CreationTimestamp
    @Column(name = "creation_date", updatable = false)
    private LocalDateTime createdDate;

    @JsonIgnore
    @Column(name = "updated_date")
    @UpdateTimestamp
    private LocalDateTime updatedDate;

    @JsonIgnore
    @Column(columnDefinition = "Bool default false")
    private Boolean isDel;


    @JsonManagedReference
    @OneToMany(mappedBy = "technic")
    private List<TechnicStatus> technicStatusList = new ArrayList<>();

    public List<TechnicStatus> getTechnicStatusList() {
        return technicStatusList;
    }

    public void setTechnicStatus(TechnicStatus technicStatus) {
        this.technicStatusList = new ArrayList<>();
        this.technicStatusList.add(technicStatus);
    }

第二：

@Entity
@Getter
@Setter
@NoArgsConstructor
public class TechnicStatus implements Serializable  {



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

    @JsonBackReference
    @ManyToOne
    private Technic technic;

    @JsonManagedReference
    @ManyToOne
    private Status status;

    private Boolean isGarantia;

    private Boolean isLizing;

    private LocalDate visitedDate;

    private LocalDate notWorkDate;

    private String description;

    @JsonIgnore
    private boolean isActive;

    @JsonIgnore
    @CreationTimestamp
    @Column(name = "creation_date", updatable = false)
    private LocalDateTime createdDate;
}

我想从包含每个对象Technic中的List的数据库中获取结果，我有List technicStatusList = new ArrayList <>（），其中我只想拥有一个TechnicStatus，其值为isActive = true。

为此，我正确执行相同的JPQL查询：

TypedQuery<Technic> query = em.createQuery("Select t  from Technic t join TechnicStatus ts on t.id = ts.technic.id where t.isDel=false and ts.isActive=true and t.farm.id=:farmId order by t.techGroup.name, t.techType.name, t.techMark.name", Technic.class);

但是得到一个包含TechnicStatus的结果，该结果将返回带有true和false（TechnicStatus.isActive = true，TechnicStatus.isActive = false）的TechnicStatus。

我想通过本机查询获得结果：

SELECT 
    *
FROM
    technic
        JOIN
    technic_status ON technic.id = technic_status.technic_id
WHERE
    technic.is_del = FALSE
        AND technic_status.is_active = TRUE
        AND technic.farm_id = 1722

Answer 1

与技术人员相关联的TechnicalStatus列表将始终是您的映射所定义的完整列表。

基本上，您有2个选择。如果您只对状态为Active的TechnicalStatus感兴趣，则可以在关联上使用非便携式的，特定于Hibernate的@Where子句。

@JsonManagedReference
@OneToMany(mappedBy = "technic")
@Where("active = 1")
private List<TechnicStatus> technicStatusList = new ArrayList<>();

https://dzone.com/articles/hibernate-where-clause

否则，您要做的就是从查询方法中返回技术状态列表，这不是您想要的，而是您所拥有的全部。

Answer 2

无法在查询条件中过滤相关集合。您可以通过对TechnicalStatus进行选择来获得它：select ts from TechnicStatus ts join Technic t where ...

我注意到的其他事情：

添加新状态时，您正在覆盖现有状态列表：

public void setTechnicStatus(TechnicStatus technicStatus) {
     this.technicStatusList = new ArrayList<>();
     this.technicStatusList.add(technicStatus);
}

在字段声明中初始化technicStatusList。技术中的添加方法：

public void addTechnicStatus(TechnicStatus technicStatus) {
    getTechnicStatusList().add(technicStatus);
    technicStatus.setTechnic(this);
}

我注意到的其他事情：

使用连接时，请勿使用on t.id = ts.technic.id。 JPA会在您编写以下内容时创建正确的本机SQL：join TechnicStatus ts WHERE ...

JPQL-带过滤器的JOIN查询

2 个答案: