is not mapped 错误改正

Posted 2020-09-17 谢维开

我出现的错误是：oorg.hibernate.hql.ast.QuerySyntaxException: DEPT is not mapped [from DEPT]

配置文件如下：

 

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="cn.lex.entity">

    <class name="Dept" table="DEPT">
        <id name="deptno" column="deptno">
            <generator class="native"/>
        </id>
        <property name="dname"></property>
        <property name="loc"></property>
    </class>

</hibernate-mapping
>

代码如下：

 

package cn.lex.test;

import cn.lex.entity.Dept;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.util.List;

/**
 * Created by accp on 2017/1/9.
 */
public class SecondTest {
    Session session;
    Transaction tx;
    @Before
    public void before(){
        Configuration cfg=new Configuration().configure();
        SessionFactory factory=cfg.buildSessionFactory();
        session=factory.openSession();
        tx=session.beginTransaction();
    }

    @Test
    public void page(){
        String hql="from DEPT order by DEPTNO";
        //创建query对象
       Query query = session.createQuery(hql);
       //每页显示几条数据
       int pageSize=2;
       //设置第一页
        int pageIndex=1;
       //设置每页显示的最大记录数
       query.setMaxResults(pageSize);
       //设置从第几条开始输出
       query.setFetchSize((pageIndex-1)*pageSize);
        List<Dept> list = query.list();
        for (Dept dept:list) {
            System.out.println("部门编号："+dept.getDeptno());
        }

    }

    @After
    public void after(){
        tx.commit();
        session.close();
    }

}

 

而出现这个错误的根本原因是hql语法里面是POJO（Plain Ordinary Java Object）对象而不是table.所以改成这样就可以了：

List<Dept> list=session.createQuery("from Dept order by DEPTNO”).list();

特记于此！以备勿忘！