Question

ProcessSolution实体：

@Entity
@Table(name="process_solution")
public class ProcessSolution implements Serializable {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="process_id", columnDefinition="INT(10) UNSIGNED")
    private Integer processId;

    @Column(name="process_name", length=120, nullable=false)
    private String processName;

    @ElementCollection(fetch=FetchType.LAZY)
    //@LazyCollection(LazyCollectionOption.FALSE)
    //@Fetch(FetchMode.Select)
    @JsonIgnore
    @CollectionTable(name="process_solution_step", 
        joinColumns=@JoinColumn(name="process_id"),
        foreignKey=@ForeignKey(name="fk_process_solution_step_process_id")
    )
    @Column(name="solution_step", length=200, nullable=false)
    private List<String> processSolutionSteps = new ArrayList<>();

    @ManyToOne
    @JoinColumn( name="category_id", columnDefinition="INT(10) UNSIGNED",nullable=false,
        foreignKey=@ForeignKey(name="fk_process_solution_category")
    )
    private Category category;

    @ManyToMany(fetch=FetchType.LAZY)
    @JoinTable(name="process_solution_employee",
        joinColumns={@JoinColumn(name="process_id")},
        inverseJoinColumns={@JoinColumn(name="emp_id",columnDefinition="INT(10) UNSIGNED")},
        foreignKey=@ForeignKey(name="fk_process_employee_process_solution_process_id"),
        inverseForeignKey=@ForeignKey(name="fk_process_employee_employee_emp_id")
    )
    private Set<Employee> employees = new HashSet<>();

    // Getters/Setters
}

我正在 DAO中执行HQL查询：

@Override
public ProcessSolution getProcessSolution(Integer processId) {
    Session session = this.sessionFactory.openSession();
    final String GET_PS = "SELECT ps FROM ProcessSolution ps JOIN FETCH ps.processSolutionSteps JOIN FETCH ps.employees WHERE ps.processId = :processId";
    //ProcessSolution processSolution = session.get(ProcessSolution.class, processId);
    ProcessSolution processSolution = ( ProcessSolution ) session.createQuery(GET_PS)
                                        .setInteger("processId", processId).uniqueResult();
    session.close();
    return processSolution;
}

我的问题是我正在ElementCollection processSolutionSteps重复（多行）。
所以我将其从 List<> 更改为 Set<> ，现在我得到了正确的结果，但订单未保留。

我尝试过：

对于Set，我尝试LinkedHashSet，但问题仍然存在。
来自here的@LazyCollection（LazyCollectionOption.FALSE）
来自其他 SO 来源的@Fetch（FetchMode.Select）

任何想法如何解决这个问题。

更新：
示例数据：

**process_solution**

+---------------+----------------+
|  process_id   |  process_name  |
+---------------+----------------+
|      3        |  process 1     |
+---------------+----------------+

**process_solution_step**

+---------------+----------------+
|  process_id   |  solution_step |
+---------------+----------------+
|      3        |    step 1      |
+---------------+----------------+
|      3        |    step 2      |
+---------------+----------------+

如果我打印处理解决方案步骤，我会得到结果

第1步
第1步
第2步
第2步

如果我打印员工Lenth，我得到了正确的结果。

Hibernate HQL Join Fetch返回重复的行

0 个答案: