如何使用spring data JPA在子类对象上编写查询方法？

Question

我想通过spring data JPA中的查询方法从子类中获取数据。不想使用jpql或标准API。我想获得所有与指定accountType和User的连接。我知道jpql以及标准api将完成这项工作，但我想用JPA查询方法实现这一点。下面是我的实体和回购代码。

这是主实体类

@Entity
public class Connection {

    @Id
    @GeneratedValue(generator = "UUID")
    @GenericGenerator(
            name = "UUID",
            strategy = "org.hibernate.id.UUIDGenerator"
    )
    @Column(name = "Connection_Id", nullable = false, updatable = false)
    private String id;

    @Column(name = "User_Id", nullable = false)
    private String userId;

    @Column(name = "Name", nullable = false, length = 64)
    private String name;

    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "Connection_Type_Id")
    private ConnectionType connectionType;
    
    // default constructor
    
    // getter and setter
    
    }

@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public abstract class ConnectionType {

    @Id
    @GeneratedValue(generator = "UUID")
    @GenericGenerator(
            name = "UUID",
            strategy = "org.hibernate.id.UUIDGenerator"
    )
    @Column(name = "Id", nullable = false)
    private String id;

    @OneToOne(mappedBy = "connectionType")
    private Connection connection;
    
    // default constructor
    
    // getter setter
}

@Entity
public class EmailAccount extends ConnectionType {
    
    @Column(name = "Username", nullable = false)
    private String username;
    
    @Column(name = "Password", nullable = false)
    private String password;
    
    
    @Column(name = "Account_Type", nullable = false)
    @Enumerated(value = EnumType.STRING)
    private AccountType accountType;
    
    @Column(name = "FullName")
    private String fullName;
    
    // default constructor
    
    // getter setter
    
}

@Entity
public class OtehrAccount extends ConnectionType {

    @Column(name = "Client_Id", nullable = false)
    private String clientId;
    
    @Column(name = "Client_Secret", nullable = false)
    private String secret;
    
    // default constructor
    
    // getter and setter
    
}

下面是存储库

public interface ConnectionRepository extends JpaRepository<Connection, String> {

    // Query Method that i want to write but is not valid.
    List<Connection> findByUserIdAndconnectionTypeAccountType(String userId, AccountType accountType);

}

repo中的findByUserIdAndconnectionTypeAccountType方法不正确，所以我只想知道天气如何，是否可以根据子类属性编写得到结果的方法？

Answer 1

为了澄清一下，“JPA查询方法”实际上是“Spring Data JPA查询方法”，所以这不是Hibernate问题。在JPQL/HQL中，这种子类型访问通常通过使用treat运算符来工作，或者在HQL中，它也隐式地工作。由于Spring Data JPA文档没有提到treat操作符，所以我认为这是不可能的：https://docs.Spring.io/Spring-Data/JPA/docs/current/reference/html/#repositories.query-methods.query-creatation