package myHibernate;
/** 测试简单的HQL语句* 2010年4月9日 23:36:54* */
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import junit.framework.TestCase;
public class HQLTest extends TestCase {public void intiData() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();Classes classes = new Classes();classes.setName("713");session.save(classes);Student student1 = new Student();Student student2 = new Student();student1.setCreateTime(new Date());student2.setCreateTime(new Date());student1.setName("小妹");student2.setName("小桂");student1.setClasses(classes);student2.setClasses(classes);session.save(student1);session.save(student2);tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}public void testHQL_1() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();//小%要加单引号哦//注意返回的结果，此处查询的是属性而不是对象，故返回的是与该属性同类型的属性列表List studentName = session.createQuery("select name from Student where name like '小%'").list();Iterator iter = studentName.iterator();while(iter.hasNext()){String name = (String) iter.next();System.out.println(name);}tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
//查询多个属性public void testHQL_2() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();//如果查询多个属性则返回的是由Object数组组成的list——每个数组代表一组属性。//数组的长度取决于select语句中属性的个数List studentName = session.createQuery("select id,name from Student").list();Iterator iter = studentName.iterator();while(iter.hasNext()){   Object objects[]= (Object[]) iter.next();  System.out.print("id: "+objects[0]+" ");
/*    int id =(Integer)objects[0];System.out.println("id+10:"+(id+10));*/System.out.println("name: "+objects[1]);  }  tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
//查询多个属性，并且返回的是一个具体的类型(如过觉得Object不够对象化的话)，而不是Object
//注意必须写构造方法，包括无参的(原则上要求)public void testHQL_3() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();//此时list中为Student对象List studentName = session.createQuery("select new Student(id,name) from Student").list();Iterator iter = studentName.iterator();while(iter.hasNext()){Student student = (Student) iter.next();System.out.println(student.getId()+" "+student.getName());  }  tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
//使用别名进行查询,可以使用as关键子也可以不用public void testHQL_4() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();//  List studentName = session.createQuery("select s.id,s.name from Student s").list();//使用了as关键字List studentName = session.createQuery("select s.id,s.name from Student as s").list();Iterator iter = studentName.iterator();while(iter.hasNext()){   Object objects[]= (Object[]) iter.next();  System.out.print("id: "+objects[0]+" ");System.out.println("name: "+objects[1]);  } tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/**查询实体对象*可以采用别名也可以不用* */ public void testHQL_5() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();// List studentName = session.createQuery("from Student").list();// List studentName = session.createQuery("from Student s").list();List studentName = session.createQuery("from Student as s").list();Iterator iter = studentName.iterator();while(iter.hasNext()){   Student s =(Student)iter.next();System.out.println(s.getName());} tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/** 采用select查询实体的话一定要用别名* */public void testHQL_6() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();// List studentName = session.createQuery("from Student").list();// List studentName = session.createQuery("from Student s").list();List studentName = session.createQuery("select s from Student as s").list();Iterator iter = studentName.iterator();while(iter.hasNext()){   Student s =(Student)iter.next();System.out.println(s.getName());} tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/** 采用迭代接口（Iterator）进行查询* 会有"N+1"问题出现：* N:发出N条语句到数据库进行查询(每个记录一条语句)* 1：发出查询id列表的语句* 原因：迭代接口使用缓存（session）,通过查询出来的id到缓存中去找，找不到就会到数据库中去找* */ public void testHQL_7() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();// List studentName = session.createQuery("from Student").list();Iterator iter = session.createQuery("select s from Student as s").iterate();while(iter.hasNext()){   Student s =(Student)iter.next();System.out.println(s.getName());} tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/** 先执行用list接口进行的查询再执行iterator接口的查询* */public void testHQL_8() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();// List studentName = session.createQuery("from Student").list();List students = session.createQuery("from Student").list();Iterator iter1 = students.iterator();while(iter1.hasNext()){Student student = (Student) iter1.next();System.out.println(student.getId()+" "+student.getName());  } //由于上面先用list进行了一次查询，故缓存中存在了这些对象，下面用iterate进行//查询时到缓存中进行查找，找得到这些对象，故只发出了一条语句：查询id的语句//总结：在有缓存的前提下使用iterate会提高效率Iterator iter = session.createQuery("select s from Student as s").iterate();while(iter.hasNext()){   Student s =(Student)iter.next();System.out.println(s.getName());} tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/** 简单条件查询* 可以采用？方式进行查询，代表一个参数* 参数的索引从0开始* */public void testHQL_9() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();  
/*   Query query =  session.createQuery("select name from Student where name like ?");query.setParameter(0, "%王");Iterator iter = query.list().iterator();*///采用方法链的方式：Iterator iter = session.createQuery("select name from Student where name like ?").setParameter(0, "小%").list().iterator();while(iter.hasNext()){System.out.println(iter.next());  }  tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/** 采用：参数名称的方式* */ public void testHQL_10() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();  
/*   Query query =  session.createQuery("select name from Student where name like ?");query.setParameter(0, "%王");Iterator iter = query.list().iterator();*///采用方法链的方式：Iterator iter = session.createQuery("select name from Student where name like :name").setParameter("name", "小%").list().iterator();while(iter.hasNext()){System.out.println(iter.next());  }  tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}/** 采用：参数名称的方式2:in方法* */ public void testHQL_11() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();  Query query =  session.createQuery("select name from Student where id in(:myids)");Object ids[] = new Object[]{1,2,3};query.setParameterList("myids",ids);Iterator iter = query.list().iterator();while(iter.hasNext()){System.out.println(iter.next());  }  tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/** 附加日期条件1* */public void testHQL_12() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();Query query =  session.createQuery("select name from Student where date_format(createTime,'%Y-%m-%d')=?");query.setParameter(0,"2010-04-10");Iterator iter = query.list().iterator();while(iter.hasNext()){System.out.println(iter.next());  }  tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/*
* 附加日期条件2
* 【注意】写的MM,而不是小写的mm  m是小时中的分钟数     M是年中的月份
* 【重要】掌握定义日期的方法
* */ public void testHQL_13() {Session session = null;Transaction tx = null;SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");try {session = HibernateUtils.getSession();tx = session.beginTransaction();Query query =  session.createQuery("select name from Student where createTime between ? and ?");//要求参数必须是一个日期Date beginTime=new Date(),endTime=new Date();try {beginTime = sdf.parse("2010-02-10 00:00:00");endTime = sdf.parse("2010-04-10 23:59:59");} catch (ParseException e) {e.printStackTrace();}query.setParameter(0,beginTime);query.setParameter(1,endTime);Iterator iter = query.list().iterator();while(iter.hasNext()){System.out.println(iter.next());  }  tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
/** 使用SQL语句* */public void testHQL_14() {Session session = null;Transaction tx = null;try {session = HibernateUtils.getSession();tx = session.beginTransaction();Query query =  session.createSQLQuery("select * from student");Iterator iter = query.list().iterator();while(iter.hasNext()){Object obj[] = (Object[]) iter.next();System.out.println(obj[0]+" "+obj[1]);}  tx.commit();} catch (HibernateException e) {e.printStackTrace();if (tx != null)tx.rollback();} finally {HibernateUtils.closeSession(session);}}
}