Hibernate HQL 对象查询1

最新推荐文章于 2025-11-24 15:28:22 发布

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文章标签：

#Hibernate #junit

本文介绍使用Hibernate框架通过不同HQL语句查询Student实体对象的方法，包括基本的查询语句及别名使用等。

import java.util.Iterator;
import java.util.List;

import org.hibernate.Session;

import junit.framework.TestCase;

/**
* 实体对象查询
* @author Administrator
*
*/
public class SimpleObjectQueryTest1 extends TestCase {

    public void testQuery1() {
        Session session = null;
        try {
            session = HibernateUtils.getSession();
            session.beginTransaction();

            //返回Student对象的集合
            //可以忽略select
            List students = session.createQuery("from Student").list();
            for (Iterator iter=students.iterator(); iter.hasNext();) {
                Student student = (Student)iter.next();
                System.out.println(student.getName());
            }
            session.getTransaction().commit();
        }catch(Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally {
            HibernateUtils.closeSession(session);
        }
    }

    public void testQuery2() {
        Session session = null;
        try {
            session = HibernateUtils.getSession();
            session.beginTransaction();

            //返回Student对象的集合
            //可以忽略select,表可以使用别名
            List students = session.createQuery("from Student s").list();
            for (Iterator iter=students.iterator(); iter.hasNext();) {
                Student student = (Student)iter.next();
                System.out.println(student.getName());
            }
            session.getTransaction().commit();
        }catch(Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally {
            HibernateUtils.closeSession(session);
        }
    }

    public void testQuery3() {
        Session session = null;
        try {
            session = HibernateUtils.getSession();
            session.beginTransaction();

            //返回Student对象的集合
            //可以忽略select,表可以使用as命名别名
            List students = session.createQuery("from Student as s").list();
            for (Iterator iter=students.iterator(); iter.hasNext();) {
                Student student = (Student)iter.next();
                System.out.println(student.getName());
            }
            session.getTransaction().commit();
        }catch(Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally {
            HibernateUtils.closeSession(session);
        }
    }

    public void testQuery4() {
        Session session = null;
        try {
            session = HibernateUtils.getSession();
            session.beginTransaction();

            //返回Student对象的集合
            //使用select查询实体对象，必须采用别名
            List students = session.createQuery("select s from Student as s").list();
            for (Iterator iter=students.iterator(); iter.hasNext();) {
                Student student = (Student)iter.next();
                System.out.println(student.getName());
            }
            session.getTransaction().commit();
        }catch(Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally {
            HibernateUtils.closeSession(session);
        }
    }


    public void testQuery5() {
        Session session = null;
        try {
            session = HibernateUtils.getSession();
            session.beginTransaction();

            //不支持select * from .....这样的查询语句
            List students = session.createQuery("select * from Student").list();
            for (Iterator iter=students.iterator(); iter.hasNext();) {
                Student student = (Student)iter.next();
                System.out.println(student.getName());
            }
            session.getTransaction().commit();
        }catch(Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally {
            HibernateUtils.closeSession(session);
        }
    }

}