Hibernate加入两个表并获取所有记录？

Hibernate加入两个表并获取所有记录？

使用ORM工具时，您需要考虑Java对象。

根据您的问题，我认为您要编写的查询看起来像：

public List<Category> getCategoryList(int id) {    List<Category> groupList;    Session session = sessionFactory.getCurrentSession();    Query query = session.createQuery("select c from Category c join fetch c.events where c.parentCategory.categoryId = 1");    //query.setParameter("id", id);    groupList = query.list();    return groupList;}

使用ORM的好处之一是它为您解决了完全联接查询。

为此，您需要按如下所示更新类模型：

import java.io.Serializable;import java.util.Date;import javax.persistence.*;@Entity@Table(name = "events")public class Event implements Serializable {    private static final long serialVersionUID = 1L;    @Id    @GeneratedValue(strategy = GenerationType.IDENTITY)    @Column(name = "event_id")    private int eventId;    @Column(name = "event_name")    private String eventName;    @Column(name = "event_description")    private String eventDescription;    @ManyToOne    @JoinColumn(name = "category_i")    private Category category;    @Column(name = "is_trending_event")    private Integer isTrendingEvent;    @Column(name = "image_url")    private String imageUrl;    private Integer status;    @Column(name = "created_date")    @Temporal(javax.persistence.TemporalType.DATE)    private Date createdDate;    @Column(name = "last_updated_date")    @Temporal(javax.persistence.TemporalType.DATE)    private Date lastUpdatedDate;    ...}

和

import java.io.Serializable;import java.util.Date;import javax.persistence.*;@Entity@Table(name = "category")public class Category implements Serializable {    private static final long serialVersionUID = 1L;    @Id    @GeneratedValue(strategy = GenerationType.IDENTITY)    @Column(name = "category_id")    private int categoryId;    @Column(name = "category_name")    private String categoryName;    @ManyToOne    @JoinColumn(name="parent_category_id")    private Category parentCategory;    @Column(name = "created_date")    @Temporal(javax.persistence.TemporalType.DATE)    private Date createdDate;    @Column(name = "last_updated_date")    @Temporal(javax.persistence.TemporalType.DATE)    private Date lastUpdatedDate;    @oneToMany(mappedBy="category")    private List<Event> events;    ...}