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我正在使用spring rest在hibernate中创建一个Web应用程序,并且我卡在两个表格之间。我想要映射一个表列与另一个表列。我已经在jsp中完成了,但现在我想在hibernate中完成。我从alert表中获取author_id,然后我想从user_table中获取该作者id的配置文件图片。如何在休眠状态下使用另一个表格列来映射表格列
JSP代码:
<%
String sql = "select author_id from alert where id=2";
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(sql);
while(rs.next()){
String aid = rs.getString("author_id");
String sql1 = "select profile_img from user_table where id='"+aid+"'";
Statement st1 = con.createStatement();
ResultSet rs1 = st1.executeQuery(sql1);
while(rs1.next()){
String image_name = rs1.getString("profile_img");
}
}
%>
我想这样做在hibernate.Here是我Alert类
@Entity
@Table(name="alert")
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class Alert implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue
@Column(name="id")
private long id;
@Column(name="author_id")
private long author_id;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public long getAuthor_id() {
return author_id;
}
public void setAuthor_id(long author_id) {
this.author_id = author_id;
}
这里是我的User类
@Entity
@Table(name="user_table")
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class User implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue
@Column(name="id")
private long id;
@Column(name="profile_img")
private String img_name;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getImg_name() {
return img_name;
}
public void setImg_name(String img_name) {
this.img_name = img_name;
}
}
这里是我的DAO等级:
@Autowired
SessionFactory sessionFactory;
Session session = null;
Transaction tx = null;
public User getUserById(long id) throws Exception {
session = sessionFactory.openSession();
User user = (User) session.load(User.class, new Long(id));
tx = session.getTransaction();
session.beginTransaction();
tx.commit();
return user;
}
@SuppressWarnings({ "unchecked", "rawtypes" })
public List<Alert> getAlertById(long id) throws Exception {
session = sessionFactory.openSession();
Criteria cr = session.createCriteria(Alert.class);
cr.add(Restrictions.eq("alert_viewer_id", id));
List alert = cr.list();
tx = session.getTransaction();
session.beginTransaction();
tx.commit();
return alert;
}
请帮我,我被困在冬眠。
哪里会创建警报对象? –
在上面的SQL代码中,您有一个警报ID。您启动一个SQL查询以获取具有该ID的警报的作者ID。然后,您再次启动第二个SQL查询,以便使用先前检索的ID获取用户的配置文件映像。使用Hibernate,如果你使用'session.createCriteria(Alert.class).add(Restrictions.eq(“id”,alertId).uniqueResult()',你将得到一个Alert对象,其id等于'alertId'变量,这相当于上面的第一个查询,然后你只需在'alert'对象上''alert.getAuthor()。getImg_name()'' – manish
兄弟请更改我的代码并发布我无法理解,因为我在休眠 –