Question

这是我担心的休眠状态，请帮我解决这个问题

g.V().hasLabel("my-label").toList()

这是我的休眠程序的重要部分

@Entity
@Table(name="nse_table")
public class retrainDto implements Serializable{

    @Id
    @Column(name="company_Id")
    private int companyId;

    @Column(name="company_symbol")
    private String companySymbol;

    // some other columns omitted

}

}

public class retrainDao {

public Scanner sc=new Scanner(System.in);
Configuration cfg=new Configuration().configure();

SessionFactory sf=cfg.buildSessionFactory();
Session ses=sf.openSession();
Transaction tx=ses.beginTransaction();

 public void saveRetrain(retrainDto dto) {
    Configuration cfg=new Configuration();
    cfg.configure();
    SessionFactory sf=cfg.buildSessionFactory();
    Session ses=sf.openSession();
    Transaction tx=ses.beginTransaction();
    retrainDto redto=new retrainDto();
    ses.save(dto);
    tx.commit();
}
public retrainDto update(int primarykey) {
    Session ses=null;
    Transaction tx=null;
    try {
        ses=sf.openSession();
        tx=ses.beginTransaction();
        retrainDto redto=new retrainDto();
        System.out.println("give primary key");

        System.out.println("give company id :");
        redto.setCompanyId(sc.nextInt());
        System.out.println("give company symbol");
        redto.setCompanySymbol(sc.next());

        // set other columns

        redto=ses.load(retrainDto.class, new Integer(primarykey));
        System.out.println("data updated succesfully");
        ses.save(redto);
        tx.commit();

    }catch(HibernateException e) {e.printStackTrace();}finally {if(ses!=null)ses.close();}
    return null;
}
public retrainDto readData(int primarykey) {
Session ses=null;
Transaction tx=null;
retrainDto redto=null;

    try {
        ses=sf.openSession();
        tx=ses.beginTransaction();

        System.out.println("confirm data  want to retrieve");
        redto=ses.get(retrainDto.class,sc.nextInt());
        System.out.println(redto);
        tx.commit();
    }catch(HibernateException e) {
        e.printStackTrace();}finally{if(ses!=null)ses.close();}
    return null;
    }
public retrainDto readbyhql(String name) {
    Session ses=null;
    Transaction tx=null;
    retrainDto redto=null;
    try {
        ses=sf.openSession();
        tx=ses.beginTransaction();
        System.out.println("try part");
        String hql="FROM retrainDto WHERE companySymbol=?";
        Query query=ses.createQuery(hql,retrainDto.class);
        query.setParameter(0, name);
        redto=(retrainDto)((org.hibernate.query.Query)query).uniqueResult();
        System.out.println("fetching  data");
        System.out.println(redto);
        tx.commit();
    }catch(HibernateException e) {
        e.printStackTrace();
    }finally{if (ses!=null)ses.close();}
    return redto;

}
}



   public class retrainTest {

    public static void main(String[] args) {


    Scanner sc=new Scanner(System.in);
    retrainDto dto=new retrainDto();
    /*System.out.println("give id :");
    dto.setRetrainId(sc.nextInt());
    System.out.println("give name :");
    dto.setRetrainName(sc.next());
    System.out.println("give percentage :");
    dto.setRetrainPercentage(sc.nextInt());

    System.out.println("created successfully");*/
    retrainDao dao=new retrainDao();
    /*dao.saveRetrain(dto);
    System.out.println("saved successfully");*/
    System.out.println("update id please");
    dao.update(sc.nextInt());
    /*System.out.println("give data to read :");
    dao.readData(sc.nextInt());*/
    /*System.out.println("sql by reading is started please enter the                 symbol :");
    dao.readbyhql(sc.next());
    System.out.println("completed reading");*/
}

我真的很困惑，无法为此找到解决方案，我到处搜索了bt，但我没有解决方案，任何人都可以清除我出了错的地方以及需要修改的内容才能工作预先感谢！

Answer 1

您只能更新受管理实体。为了获得托管实体，您必须首先通过按ID提取实体将其附加到休眠会话。在您的update(int primaryKey)方法中，您应该将代码上移：

redto=ses.get(retrainDto.class, new Integer(primarykey));

并放置而不是

retrainDto redto=new retrainDto();

P.S。如果要创建新实体而不是更新现有实体，则必须不手动为已构造实例分配ID属性（redto.setCompanyId(sc.nextInt());），因为数据库将为你做

hbernate org.hibernate.PersistentObjectException：未初始化的代理传递给org.hibernate.event.internal.DefaultSave的save（）

1 个答案: