Question

我有一个Customer实体：

@Entity
@Table(name = "customer")
@Data
public class Customer {

    @Id
    @GeneratedValue(generator = "uuid2")
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    private UUID id;

    @Column(unique = true)
    private String name;

    @ManyToMany(cascade = {
            CascadeType.PERSIST,
            CascadeType.MERGE
    })
    @JoinTable(name = "customer_system_mapping",
            joinColumns = @JoinColumn(name = "customer_id"),
            inverseJoinColumns = @JoinColumn(name = "system_id")
    )
    private List<System> systems;

    public Customer() {}

    public Customer(String name) {
        this.name = name;
    }

    public Customer(UUID id,
                    String displayName
                    List<System> systems) {
        this.id = id;
        this.name = name;
        this.systems = systems;
    }
}

和System实体：

@Entity
@Table(name = "system")
@Data
public class System {

    @Id
    @GeneratedValue(generator = "uuid2")
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    private UUID id;

    private String name;

    public System() {}

    public System(UUID id, String name) {
        this.id = id;
        this.name = name;
    }
}

（@data注释来自Project Lombok并自动生成getter和setter）。

我还有一个CustomerRepository（使用property expression根据id的{{1}}属性进行查询：

System

我希望发生的是，调用findBySystems_id会使用@Repository public interface CustomerRepository extends PagingAndSortingRepository<Customer, UUID>, JpaSpecificationExecutor<Customer> { Page<Customer> findBySystems_id(UUID id, Pageable pageable); } System返回映射到JoinTable 的所有客户。如果customer_system_mapping的条目与Customer匹配，则System会有customer_system_mapping。

这是JPA生成的SQL：

[customer_id, system_id]

这是SQL绑定的日志：

select
    customer0_.id as id1_0_,
    customer0_.name as name_5_0_
    from
        customer customer0_ 
    left outer join
        customer_system_mapping syst1_ 
            on customer0_.id=syst1_.customer_id 
    left outer join
        system syst2_ 
            on syst1_.system_id=syst2_.id 
    where
        syst2_.id = ? limit ?;

当我将生成的SQL代码和绑定参数复制/粘贴到MySQL中时，我得到一个结果（正确的行为）。但是当我致电binding parameter [1] as [BINARY] - [3023f335-5d28-4244-996b-286a5f5c3446]时，我得不到任何结果。

Answer 1

属性的第一个字母应为大写

 Page<Customer> findBySystems_Id(UUID id, Pageable pageable);

查询在MySQL中有效，但在使用Spring Data存储库时不返回任何结果

1 个答案: