Question

我有一个关于使用嵌套的“ custom”子列表创建具有自定义响应（弹簧投影）的本机查询的问题，即我正在尝试使用嵌套的子列表生成JSON输出。

子实体为：

@Entity
public class Child {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;

    @NotNull
    @Column(nullable = false)
    private String firstName;

    @NotNull
    @Column(nullable = false)

    private String secondName;

    @Enumerated(EnumType.STRING)
    private Gender gender;

    private Date dateOfBirth;

    private String phone;   

    @ManyToOne
    @JoinColumn(name="child_id")
    private List<Parent> parents = new ArrayList<Parent>();
//...
}

父实体例如：

@Entity
public class Parent {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;

    @NotNull
    @Column(nullable = false)
    private String firstName;

    @NotNull
    @Column(nullable = false)
    private String secondName;

    private Date dateOfRegistration;

    @OneToMany(fetch = FetchType.LAZY)
    private List<Child> child = new ArrayList<Child>();
    //...
}

投影界面：

public interface ChildProjectionInterface {

    public int getParentId();

    public Date getFirstName();

    public List<ChildResponse> getChildData();

    interface ChildResponse {

        public int getChildID();
        public String getFirstName();

    }
}

查询（但显然不起作用）：

@Query(value = "SELECT p.id AS parentId, p.firstName AS firstName, c.id AS childData.childId, c.firstName AS childData.firstName FROM parent p LEFT JOIN child c ON p.child_id = c.child_id AND p.secondName = :secondName", nativeQuery = true)
    List<ChildProjectionInterface> getListWithSubList(@Param(value ="secondName") String secondName);

我正在阅读，研究和尝试..但是没有任何效果（我看到了https://medium.com/swlh/spring-data-jpa-projection-support-for-native-queries-a13cd88ec166，看到了“ for json auto”子句，但没有看到spring jpa等）

Answer 1

您尝试过jpa fetch运算符吗？

@Query("select p from parent p left join fetch p.child c where p.secondName = :secondName")

带有子列表的Spring JPA投影

1 个答案: