我開始學習Hibernate,並試圖從postgresql數據庫中列出實體。我有一張桌面「dbuser」。然後我有一個Dbuser類的映射。從給定字段hibernate排序的數據庫列表實體
@Entity
@Table(name = "dbuser", schema = "public", catalog = "postgres")
public class DbuserEntity {
private int id;
private String username;
private String createdBy;
private Date createdDate;
private String firstName;
private String lastName;
@OrderBy("firstName")
public List<DbuserEntity> dbusers = new ArrayList<DbuserEntity>();
//constructors
@Id
@SequenceGenerator(name="pk_sequence",sequenceName="entity_id_seq", allocationSize=1)
@GeneratedValue(strategy=GenerationType.AUTO,generator="pk_sequence")
@Column(name = "id")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Basic
@Column(name = "username")
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
// other getters and setters, equals etc.
然後,我有方法,一流的服務,從表中讀取所有實體:
public List readAll() {
HibernateUtils hibernateUtils = new HibernateUtils();
Session session = null;
List users = new ArrayList<DbuserEntity>();
try {
session = hibernateUtils.getSessionFactory().openSession();
session.beginTransaction();
users = session.createQuery("FROM DbuserEntity ").list();
session.beginTransaction().commit();
} catch (HibernateException e) {
session.beginTransaction().rollback();
e.printStackTrace();
} finally {
if (session != null) {
if (session.isOpen()) {
session.close();
}
}
}
return users;
}
在main()方法,我列出的所有實體從表。我希望它按firstName排序。
public static void main(String[] args) {
Service service = new Service();
DbuserEntity db = new DbuserEntity();
List users = new ArrayList<DbuserEntity>();
users = service.readAll();
db.dbusers = users;
for (DbuserEntity dbuser : db.dbusers) {
System.out.println(dbuser.toString());
}
}
}
而這會打印出表格中的所有dbusers。
DbuserEntity{id=19, username='user2', createdby='admin', createddate=2014-11-19, firstname='john', lastname='johnson'}
DbuserEntity{id=20, username='user3', createdby='admin', createddate=2014-11-19, firstname='ivan', lastname='ivanov'}
DbuserEntity{id=26, username='newUSer', createdby='system', createddate=2014-11-21, firstname='AAA', lastname='BBB'}
但他們沒有排序。我不明白我做錯了什麼。我應該更改我的代碼以打印排序的實體?
作爲一個方面說明,如果您沒有對語句進行更改,則不需要提交或回滾。 – Kraylog 2014-11-22 15:33:57