Hibernate @Version annotation and object references an unsaved transient instance

问题

My New Project is in Hibernate 4.2.5.Final and Spring. After Login, I am storing the user object in the session. Now after successful login, I need to insert one record in the application log. Here are the classes:

Class BaseEntity

 @MappedSuperclass
public abstract class BaseEntity implements Serializable {

    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long ID;
    @Version
    private Long version;
    private Long createdBy;
    @Temporal(value = TemporalType.TIMESTAMP)
    private Date createdDate;
    private Long updatedBy;
    @Temporal(value = TemporalType.TIMESTAMP)
    private Date updatedDate;
    private String deactivatedReason;
    private String activatedReason;
    private Integer active;

    public long getID() {
        return ID;
    }

    public void setID(long iD) {
        ID = iD;
    }

    public Long getVersion() {
        return version;
    }

    public void setVersion(Long version) {
        this.version = version;
    }

    public Long getCreatedBy() {
        return createdBy;
    }

    public void setCreatedBy(Long createdBy) {
        this.createdBy = createdBy;
    }

    public Date getCreatedDate() {
        return createdDate;
    }

    public void setCreatedDate(Date createdDate) {
        this.createdDate = createdDate;
    }

    public Long getUpdatedBy() {
        return updatedBy;
    }

    public void setUpdatedBy(Long updatedBy) {
        this.updatedBy = updatedBy;
    }

    public Date getUpdatedDate() {
        return updatedDate;
    }

    public void setUpdatedDate(Date updatedDate) {
        this.updatedDate = updatedDate;
    }

    public String getDeactivatedReason() {
        return deactivatedReason;
    }

    public void setDeactivatedReason(String deactivatedReason) {
        this.deactivatedReason = deactivatedReason;
    }

    public String getActivatedReason() {
        return activatedReason;
    }

    public void setActivatedReason(String activatedReason) {
        this.activatedReason = activatedReason;
    }

    public Integer getActive() {
        return active;
    }

    public void setActive(Integer active) {
        this.active = active;
    }

}

Class Users:

package com.product.domain;

import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.Pattern;

import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.NotBlank;

import com.product.audit.IAuditLog;
import com.product.domain.base.BaseEntity;

@Entity
@Table(name = "users")
@NamedQueries({ @NamedQuery(name = "Users.findUserByUserID", query = "SELECT usr  FROM Users  as usr WHERE usr.userName = ? and usr.practice.code = ?") })
public class Users extends BaseEntity implements IAuditLog {


    private String userName;
    private String password;

    // bi-directional many-to-one association to Practice
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "practiceID")
    private Practice practice;
    //getters and setters
}

Class ApplicationEvents:

package com.product.domain;

import java.util.Date;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

@Entity
@Table(name = "applicationevents")
public class ApplicationEvents {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long ID;

    @Temporal(value = TemporalType.TIMESTAMP)
    private Date eventDate;
    private String comments;
    private Integer eventType;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "practiceID")
    private Practice practice;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "userID")
    private Users userID;

    //getters and setters

}

ApplicationEvents appEvent = new ApplicationEvents();
        appEvent.setEventType(eventType);
        appEvent.setPractice(practice);
        appEvent.setUserID(userID);
        appEvent.setComments(comments);
        appEvent.setEventDate(new Timestamp(new Date().getTime()));
        CRUDService.Save(appEvent);

When I try to save ApplicationEvent, I am getting the following error:

18:34:34.540 [http-bio-8080-exec-8] INFO  c.p.a.MyUserDetailsService - Logged User authentication sucess. UserName admin and practice Name Physicians Choice Laboratory
Hibernate: 
    /* insert com.product.domain.ApplicationEvents
        */ insert 
        into
            applicationevents
            (comments, eventDate, eventType, practiceID, userID) 
        values
            (?, ?, ?, ?, ?)
19 Sep, 2013 6:34:34 PM org.zkoss.bind.impl.ParamCall call:117
SEVERE: 
org.springframework.dao.InvalidDataAccessApiUsageException: object references an unsaved transient instance - save the transient instance before flushing: com.product.domain.Users; nested exception is org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.product.domain.Users
    at org.springframework.orm.hibernate4.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:166)
    at org.springframework.orm.hibernate4.HibernateTransactionManager.convertHibernateAccessException(HibernateTransactionManager.java:680)
    at org.springframework.orm.hibernate4.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:562)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:755)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:724)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:475)

Very Important Note: When I remove the @Version in the base entity, everything works fine.

回答1:

It is my mistake. In the users table, the particular record version column has null value. See here

回答2:

First you need to save the user.

        CRUDService.Save(userID);

Then you associate user to the ApplicationEvents

        ApplicationEvents appEvent = new ApplicationEvents();
        appEvent.setEventType(eventType);
        appEvent.setPractice(practice);
        appEvent.setUserID(userID);
        appEvent.setComments(comments);
        appEvent.setEventDate(new Timestamp(new Date().getTime()));
        CRUDService.Save(appEvent);

来源：https://stackoverflow.com/questions/18895585/hibernate-version-annotation-and-object-references-an-unsaved-transient-instanc