如何使用构造函数在选择子句中为多个表的选定列编写HQL JOIN查询
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我正在使用Constructor()在Select子句中为多个表的选定列编写HQL JOIN查询
我有以下实体： 实体1：NotificationObject.java @Entity
@Table(name="notification_object")
public class NotificationObject implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue( strategy=GenerationType.IDENTITY )
@Column( columnDefinition="INT(10) UNSIGNED" )
private Integer id;
@Column( name="entity_type_id",columnDefinition="TINYINT UNSIGNED",nullable=false )
private Short entityTypeId;
@Column( name="entity_id",columnDefinition="INT(10) UNSIGNED",nullable=false )
private Integer entityId;
@DateTimeFormat( pattern="yyyy-MM-dd" )
@Temporal( TemporalType.TIMESTAMP )
@CreationTimestamp
@Column( name="created_on"/*,nullable=false*/ )
private Date createdOn;
@OneToMany( mappedBy = "notificationObject" )
private Set<Notification> notifications = new LinkedHashSet<>();
public NotificationObject() {}
public NotificationObject(Short entityTypeId,Integer entityId) {
this.entityTypeId = entityTypeId;
this.entityId = entityId;
}
// Getters and Setters
}
实体2：NotificationChange.java @Entity
@Table(name="notification_change")
public class NotificationChange implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(columnDefinition="INT(10) UNSIGNED")
private Integer id;
@ManyToOne( fetch=FetchType.LAZY )
@JoinColumn(
name="notification_object_id",nullable=false,foreignKey=@ForeignKey(name="fk_notification_change_notification_object_noti_object_id")
)
private NotificationObject notificationObject;
@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(
name="actor_id",foreignKey=@ForeignKey(name="fk_notification_change_user_user_id")
)
private User actor;
public NotificationChange() {}
public NotificationChange( User actor ) {
this.actor = actor;
}
// Getters and Setters
}
实体3：Notification.java @Entity
@Table(name="notification")
public class Notification implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue( strategy=GenerationType.IDENTITY )
@Column( columnDefinition="INT(10) UNSIGNED" )
private Integer id;
@ManyToOne( fetch=FetchType.LAZY )
@JoinColumn(
name="notification_object_id",foreignKey=@ForeignKey(name="fk_notification_notification_object_notification_object_id")
)
private NotificationObject notificationObject;
@ManyToOne( fetch=FetchType.LAZY )
@JoinColumn(
name="notifier_id",foreignKey=@ForeignKey(name="fk_notification_user_user_id")
)
private User notifier;
@Column( name="is_seen",nullable=false )
private boolean isSeen;
@Column( name="is_viewed",nullable=false )
private boolean isViewed;
public Notification() {}
public Notification( User notifier,boolean isSeen,boolean isViewed ) {
this.notifier = notifier;
this.isSeen = isSeen;
this.isViewed = isViewed;
}
// Getters and Setters
}
实体4：User.java @Entity
@Table(name="user")
public class User implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="user_id")
private String user_id;
// Extra fields
@OneToOne(cascade=CascadeType.MERGE)
@JoinColumn(name="emp_id",columnDefinition="INT(10) UNSIGNED")
private Employee employee;
@OneToMany( mappedBy="notifier" )
private Set<Notification> notifications = new LinkedHashSet<>();
public User() {}
public User(String user_id) {
this.user_id = user_id;
}
// Getters and Setters
}
实体5：Employee.java @Entity
@Table(name="employee")
public class Employee implements Serializable {
private static final long serialVersionUID = 1L;
public Employee() { }
public Employee( String emp_id ) {
this.emp_id = emp_id;
}
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="emp_id")
private String emp_id;
@Column(name="first_name")
private String first_name;
@Column(name="last_name")
private String last_name;
// Extra fields
@OneToOne(mappedBy="employee")
@JsonBackReference
private User user;
// Getters and Setters
}
DTO 1：Notify.java public class Notify {
private Integer notificationObjectId,notificationId,notifierId,actorId,entityId;
private Short entityTypeId;
private String notifierName,actorName,message,notificationLink;
private Date createdOn;
private boolean isSeen,isViewed;
public Notify() {}
public Notify ( Integer notificationObjectId,Integer notificationId,Integer notifierId,Integer actorId,Integer entityId,Short entityTypeId,String notifierName,String actorName,String message,String notificationLink,Date createdOn,boolean isViewed ) {
// Set Values Here
}
public Notify (Integer notificationObjectId,boolean isViewed ) {
// Or Here
}
// Getters and Setters
}
我在JOINs很弱. 查询1 final String GET_NOTIFICATIONS_FOR_USER = "select new support.dto.Notify ( no.id,n.id,Integer.parseInt( n.notifier.user_id )," + "concat ( n.notifier.employee.first_name,' ',n.notifier.employee.last_name )," + "Integer.parseInt( nc.actor.user_id ),concat( nc.actor.employee.first_name,nc.actor.employee.last_name )," + "no.entityId,no.entityTypeId,no.createdOn,n.isSeen,n.isViewed ) " + "from Notification n,NotificationObject no,NotificationChange nc,User u,Employee e " + "where n.notifier.user_id = :notifierId"; 查询2 final String GET_NOTIFICATIONS_FOR_USER = "select new support.dto.Notify ( no.id,n.notifier.employee.first_name ),n.isViewed ) " + "from NotificationChange nc inner join nc.notificationObject no " + "inner join no.notifications n " + "where n.notifier.user_id = :notifierId"; 我正在接受以下异常
解决方法该错误告诉您Hibernate无法找到Notify构造函数.此外,您不能在HQL查询中添加Integer.parseInt.使用ResultSet中的预期类型,并从传入参数在构造函数内部执行转换. （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |