Hibernate提供的多种查询方式

注意：每种查询方式又含有多种重载的方法，这里只列出基础的一种。

Hibernate提供了多种查询方式：

1. Hibernate查询方式一：get查询
2. Hibernate查询方式二：load延迟加载
3. Hibernate查询方式三：HQL之createQuery，返回多条数据
4. Hibernate查询方式四：createCriteria查询，返回多条数据
5. Hibernate查询方式五：HQL之createSQLQuery，根据SQL语句返回数据

package com.ckinghan.test;import java.util.List;import org.hibernate.Criteria;import org.hibernate.Query;import org.hibernate.SQLQuery;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.Configuration;import org.hibernate.classic.Session;import org.junit.Test;import com.ckinghan.bean.User;/** * Hibernate提供了多种查询方式 * @author ckinghan */public class HibernateQueryTest {    /**     * Hibernate查询方式一：get     */    @Test    public void HibernateGetQuery(){        Configuration configuration = new Configuration().configure();        SessionFactory buildSessionFactory = configuration.buildSessionFactory();        Session currentSession = buildSessionFactory.getCurrentSession();        Transaction transaction = currentSession.beginTransaction();        Object object = currentSession.get(User.class, 1);        if(object != null && !"".equals(object)){            User user = (User) object;            System.out.println(user);        }        transaction.commit();        buildSessionFactory.close();    }    /**     * Hibernate查询方式二：load延迟加载     */    @Test    public void hibernateLoadQuery(){        Configuration configuration = new Configuration().configure();        SessionFactory buildSessionFactory = configuration.buildSessionFactory();        Session currentSession = buildSessionFactory.getCurrentSession();        Transaction transaction = currentSession.beginTransaction();        Object load = currentSession.load(User.class, 1);        if(load != null && !"".equals(load)){            User user = (User) load;            System.out.println(user);        }        transaction.commit();        buildSessionFactory.close();    }    /**     * Hibernate查询方式三：HQL之createQuery，返回多条数据     */    @Test    public void hibernateHqlQuery(){        Configuration configuration = new Configuration().configure();        SessionFactory buildSessionFactory = configuration.buildSessionFactory();        Session currentSession = buildSessionFactory.getCurrentSession();        Transaction transaction = currentSession.beginTransaction();        //注意：这里传的参数中的User是实体类名        Query createQuery = currentSession.createQuery("from User");        //通过Query类中的list()方法返回list结果集        List<User> users = createQuery.list();        System.out.println(users);        transaction.commit();        buildSessionFactory.close();    }    /**     * Hibernate查询方式四：createCriteria查询，返回多条数据     */    @Test    public void hibernateCriteriaQuery(){        Configuration configuration = new Configuration().configure();        SessionFactory buildSessionFactory = configuration.buildSessionFactory();        Session currentSession = buildSessionFactory.getCurrentSession();        Transaction transaction = currentSession.beginTransaction();        //通过实体类，将对应的数据库表中的数据全部返回        Criteria createCriteria = currentSession.createCriteria(User.class);        //通过Criteria类提供的list()方法将数据转换为List<User>类型        List<User> list = createCriteria.list();        System.out.println(list);        transaction.commit();        buildSessionFactory.close();    }    /**     * Hibernate查询方式五：HQL之createSQLQuery，根据SQL语句返回数据     */    @Test    public void hibernateHqlCreateSqlQuery(){        Configuration configuration = new Configuration().configure();        SessionFactory buildSessionFactory = configuration.buildSessionFactory();        Session currentSession = buildSessionFactory.getCurrentSession();        Transaction transaction = currentSession.beginTransaction();        //传入要查询的SQL语句         SQLQuery query = currentSession.createSQLQuery("select * from user");        //将查询到的数据封装到User实体中        query.addEntity(User.class);        //通过Query的list()方法，返回List<User>        List<User> list = query.list();        System.out.println(list);        transaction.commit();        buildSessionFactory.close();    }}