这些东西会解决你的问题
@Entity@Table(name = "category")public class FetchSubCategory implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "category_id") private Integer categoryId; @Column(name = "category_name") private String categoryName; @NotFound(action = NotFoundAction.IGNORE) @ManyToOne @JsonIgnore @JoinColumn(name = "parent_category_id") private FetchSubCategory mainCategory; @JsonSerialize(include = JsonSerialize.Inclusion.NON_EMPTY)//Avoiding empty json arrays.objects @oneToMany(mappedBy = "mainCategory", fetch = FetchType.EAGER) private List<FetchSubCategory> subCategory; public Integer getCategoryId() { return categoryId; } public void setCategoryId(Integer categoryId) { this.categoryId = categoryId; } public String getCategoryName() { return categoryName; } public void setCategoryName(String categoryName) { this.categoryName = categoryName; } public FetchSubCategory getMainCategory() { return mainCategory; } public void setMainCategory(FetchSubCategory mainCategory) { this.mainCategory = mainCategory; } public List<FetchSubCategory> getSubCategory() { return subCategory; } public void setSubCategory(List<FetchSubCategory> subCategory) { this.subCategory = subCategory; }Get your sub categories
public List<FetchSubCategory> fetchSubCategory() throws SQLException, ClassNotFoundException, IOException { List<FetchSubCategory> groupList = null; try { Session session = sessionFactory.getCurrentSession(); Query query = session.createQuery("select distinct e FROM FetchSubCategory e INNER JOIN e.subCategory m ORDER BY m.mainCategory"); groupList = query.list(); } catch (Exception e) { e.printStackTrace(); } return groupList; }
