Hibernate session.save()从查询中缺少成员

Question

hiii家伙我正在构建一个简单的招待员（这只是我项目的开始），应该通过使用MAMP为DB将任务添加到我的时间表中。我的问题是season.save（）缺少查询（" id"）的主键；我有以下代码：主要课程：

 package Model;

    import java.util.Date;
    import java.util.List;
    import org.hibernate.HibernateException;
    import org.hibernate.Session;
    import org.hibernate.SessionFactory;
    import org.hibernate.cfg.AnnotationConfiguration;

    //create exception instead of HibernateException  ToDoListDAOException
    public class HibernateToDoListDAO implements IToDoListDAO {
        SessionFactory factory = null;
        private static final HibernateToDoListDAO _instanceDAO = new HibernateToDoListDAO();

        // no need to do connection or use driver to my sql
        private HibernateToDoListDAO(){
            factory = new AnnotationConfiguration().configure().buildSessionFactory();
        }
        public static HibernateToDoListDAO getInstance()
        {
            return _instanceDAO;
        }
        @Override
        public void addMemorandums(items memorandum) throws HibernateException {
            Session session = factory.openSession();
            try{
                session.beginTransaction();
                //create the query for memorandum members
                session.saveOrUpdate(memorandum);
                System.out.println("after save : user id's = "+memorandum.getId());
                session.getTransaction().commit();
            }catch(HibernateException e )
            {
                e.printStackTrace();
                if ( session.getTransaction() != null )
                    session.getTransaction().rollback();
            }finally{
                session.close();
            }
        }
        @Override
        public void updateMemorandums(items memorandum) throws HibernateException {
            Session session = null;
            try{
                session = factory.openSession();
                session.beginTransaction();
                session.update(memorandum);
                session.getTransaction().commit();
            }catch(HibernateException e )
            {
                e.printStackTrace();
                if ( session.getTransaction() != null )
                    session.getTransaction().rollback();
            }finally{
                session.close();
            }
        }
        @Override
        public void deleteMemorandums(items memorandum) throws HibernateException {
            Session session = null;
            try{
                session = factory.openSession();
                session.beginTransaction();
                session.delete(memorandum);
                session.getTransaction().commit();
            }catch(HibernateException e )
            {
                e.printStackTrace();
                if ( session.getTransaction() != null )
                    session.getTransaction().rollback();
            }finally{
                session.close();
            }
        }
        @SuppressWarnings("unchecked")
        @Override
        public List<items> getMemorandums() throws HibernateException {
            List<items> memorandum = null;
            Session session = null;
            try{
                session = factory.openSession();
                session.beginTransaction();
                memorandum = session.createQuery("from todolists").list();
            }catch(HibernateException e )
            {
                e.printStackTrace();
                if ( session.getTransaction() != null )
                    session.getTransaction().rollback();
            }finally{
                session.close();
            } 
            return memorandum;
        }
        public static void main(String[] args) {
            @SuppressWarnings("deprecation")
            String dateTask = "26/11/2016";
            items task1 = new items(2012,"football", dateTask , "ball");
            HibernateToDoListDAO.getInstance().addMemorandums(task1);
        }
    }

项目类：

package Model;
import java.util.Date;
public class items {
    private int id;// primary key that connect to the users
    private String taskname;
    private String date;
    private String note;

    public items(){
        taskname = "basketball";
        note = "a fun game";
        date = "15/10/2016";
        id = 2012;
    }
    public items(int id, String taskName, String taskDate, String note) {
        super();
        this.taskname = taskName;
        this.date = taskDate;
        this.note = note;
        this.id = id;
    }
    public String getTaskname() {
        return taskname;
    }
    public void setTaskname(String taskname) {
        this.taskname = taskname;
    }
    public String getDate() {
        return date;
    }
    public void setDate(String date) {
        this.date = date;
    }
    public String getNote() {
        return note;
    }
    public void setNote(String note) {
        this.note = note;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
}

我正在尝试运行这个简单的程序，并且我得到的例外看起来像：

（异常）

Hibernate: insert into items (taskname, date, note) values (?, ?, ?)
org.hibernate.HibernateException: The database returned no natively generated identity value
    at org.hibernate.id.IdentifierGeneratorHelper.getGeneratedIdentity(IdentifierGeneratorHelper.java:84)
    at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:98)
    at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2329)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2836)
    at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:267)
    at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:321)
    at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204)
    at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:117)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
    at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:677)
    at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:669)
    at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:665)
    at Model.HibernateToDoListDAO.addMemorandums(HibernateToDoListDAO.java:36)
    at Model.HibernateToDoListDAO.main(HibernateToDoListDAO.java:111)

hibernate.cfg.xml：

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM 
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
   <session-factory>
   <property name="hibernate.dialect">
      org.hibernate.dialect.MySQLDialect
   </property>
   <property name="hibernate.connection.driver_class">
      com.mysql.jdbc.Driver
   </property>
   <!-- Assume test is the database name -->
   <property name="hibernate.connection.url">
      jdbc:mysql://localhost:3306/hit
   </property>
 <property name="hibernate.connection.username">hit</property>
 <property name="hibernate.connection.password">hit</property>
 <property name="show_sql">true</property>
 <!-- Mapping files -->
 <mapping resource="hibernate.mapping.xml"/>
</session-factory>
</hibernate-configuration>

hibernate.mapping.xml：

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
 "-//Hibernate/Hibernate Mapping DTD//EN"
 "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 
<hibernate-mapping>
   <!-- *********** items table   ******* -->
<!-- full class name including the packege name -->
   <class name="Model.items" table="items">
      <meta attribute="class-description">
         This class contains the the items details. 
      </meta>
      <id name="id" type="int" column="id"> <!-- primary key -->
         <generator class="native"/>
      </id>
      <property name="taskname" column="taskname" type="string"/>
      <property name="date" column="date" type="string"/>
      <property name="note" column="note" type="string"/>
   </class>
   <!-- *********** users table   ******* -->
   <!-- full class name including the packege name -->
   <class name="Model.users" table="users">
      <meta attribute="class-description">
         This class contains the users details. 
      </meta>
      <id name="id" type="int" column="id">
         <generator class="native"/>
      </id>
      <property name="name" column="name" type="string"/>
      <property name="age" column="age" type="int"/>
   </class>

</hibernate-mapping>

我正在使用MAMP作为DB（使用MySQL）。问题在于查询仅插入三个而不是四个变量（缺少" ID"成员）。有人可以帮助我解决这个问题吗？

谢谢你们。

Answer 1

您必须自动增加表的身份列，以摆脱此错误。编写Alter Table查询以具有自动增量的身份列。这应该解决您的问题