4、Hibenrate中HQL的10中查询方式

二、具体事例如下：

2.0 编写如下sql语句

create table teacher(tid number not null primary key,tname varchar2(20));
create sequence seq_teacher;
insert into teacher values(seq_teacher.nextval,'holly');
insert into teacher values(seq_teacher.nextval,'石头');
commit;
insert into teacher values(seq_teacher.nextval,'holly1');
insert into teacher values(seq_teacher.nextval,'holly2');
commit;

2.1 创建如下的javaweb项目并添加jar文件

2.2 在项目的src下创建hibernate.cfg.xml主配置文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd" >
<hibernate-configuration>
  <session-factory>
     <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
     <property name="connection.url">jdbc:oracle:thin:@127.0.0.1:1521:orcl</property>
     <property name="connection.username">scott</property>
     <property name="connection.password">tiger</property>
     <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>
     <property name="show_sql">true</property>
     <property name="format_sql">true</property>
     <mapping resource="com/entity/Teacher.hbm.xml"/>
  </session-factory>
</hibernate-configuration>

2.3 在项目的com.entity包下创建Teacher.java类

package com.entity;


public class Teacher {
    private int tid;
    private String tname;
    
    public Teacher() {
    }

    public Teacher(String tname) {
        this.tname = tname;
    }

    public Teacher(int tid, String tname) {
        this.tid = tid;
        this.tname = tname;
    }

    public int getTid() {
        return tid;
    }

    public void setTid(int tid) {
        this.tid = tid;
    }

    public String getTname() {
        return tname;
    }

    public void setTname(String tname) {
        this.tname = tname;
    }

    @Override
    public String toString() {
        return "Teacher [tid=" + tid + ", tname=" + tname + "]";
    }
    
    

}

2.4 在项目的com.entity包下创建Teacher.hbm.xm文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
<hibernate-mapping>
<class name="com.entity.Teacher" table="TEACHER">
  <id name="tid" type="java.lang.Integer" column="TID">
    <generator class="sequence">
       <param name="sequence">seq_teacher</param>
    </generator>
  </id>
  <property name="tname" type="java.lang.String" column="TNAME"/>
</class>
</hibernate-mapping>

2.5 在项目的com.util包下创建HibernateUtil.java类

package com.util;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {
    private static ThreadLocal<Session> thread=new ThreadLocal<Session>();
    private static Configuration config=null;
    private static SessionFactory factory=null;
    
    static{
        try {
            config=new Configuration().configure("/hibernate.cfg.xml");
            factory=config.buildSessionFactory();
        } catch (HibernateException e) {
            System.out.println("读取配置文件或创建工厂失败");
            e.printStackTrace();
        }
    }
    
    public static Session getSession(){
        Session session =thread.get();
        if(session==null){
            session =factory.openSession();
            thread.set(session);
        }
        return session;
    }
    public static void closeSession(){
        Session session =thread.get();
        thread.set(null);
        session.close();
        
    }

}

2.6 在项目的com.dao包下创建TeacherDao.java类

package com.dao;

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

import org.hibernate.Query;
import org.hibernate.Session;

import com.entity.Teacher;
import com.util.HibernateUtil;

public class TeacherDao {
    /**
     * 1.iterate() 延时加载查询一堆
     * 得到1+N条sql
     * 1是查询所有的sql
     * n根据id查询的n条sql
     * 延迟加载(用时在查询),关闭session的时机是读取完数据之后再关闭
     */
    public static Iterator<Teacher> hqlItertor() {
        Session session=HibernateUtil.getSession();
        //定义hql语句
        String hql="from Teacher";
        
        //创建Query查询接口对象
        Query query=session.createQuery(hql);
        
        //使用list方法查询所有返回list集合
        Iterator<Teacher> it=query.iterate();
        
        
        return it;
    }
    /**
     *  2. list()立即加载
     * 一条sql
     * 立即加载(一次性查询出所有内容(关联)放入内存)
     * 
     */
    public static List<Teacher> hqlList() {
        Session session=HibernateUtil.getSession();
        //定义hql语句
        String hql="from Teacher";
        
        //创建Query查询接口对象
        Query query=session.createQuery(hql);
        
        //使用list方法查询所有返回list集合
        List<Teacher> list=query.list();
        
        
        HibernateUtil.closeSession();
        return list;
        
    }
    /**
     * 3.根据条件查询返回集合
     * @param tname
     * @return
     */
    public static List<Teacher> hqlIf(String tname) {
        Session session=HibernateUtil.getSession();
        //定义hql语句
        String hql="from Teacher where tname='"+tname+"'";
        
        //创建Query查询接口对象
        Query query=session.createQuery(hql);
        
        //使用list方法查询所有返回list集合
        List<Teacher> list=query.list();
        
        
        HibernateUtil.closeSession();
        return list;
    }
    /**
     * 4. 占位符的使用(模糊查询)
     * @param string
     * @return
     */
    public static List<Teacher> hqlLike(String name) {
        Session session=HibernateUtil.getSession();
        //定义hql语句
        String hql="from Teacher where tname like ?";
        
        //创建Query查询接口对象
        Query query=session.createQuery(hql);
        String str="%"+name+"%";
        query.setString(0, str);
        
        //使用list方法查询所有返回list集合
        List<Teacher> list=query.list();
        
        
        HibernateUtil.closeSession();
        return list;
    }
    /**
     * 5. 按照参数名称使用(模糊查询)
     * @param string
     * @return
     */
    public static List<Teacher> hqlLikeName(String name) {
        Session session=HibernateUtil.getSession();
        //定义hql语句
        String hql="from Teacher where tname like :pname";
        
        //创建Query查询接口对象
        Query query=session.createQuery(hql);
        String str="%"+name+"%";
        query.setString("pname", str);
        
        //使用list方法查询所有返回list集合
        List<Teacher> list=query.list();
        
        
        HibernateUtil.closeSession();
        return list;
    }
    /**
     * 6. 条件查询绑定任意类型的参数:命名参数
     * @param string
     * @return
     */
    public static List<Teacher> hqlSetParam(String name) {
        Session session=HibernateUtil.getSession();
        //定义hql语句
        String hql="from Teacher where tname like :pname";
        
        //创建Query查询接口对象
        Query query=session.createQuery(hql);
        String str="%"+name+"%";
        
        query.setParameter("pname", str);
        
        //使用list方法查询所有返回list集合
        List<Teacher> list=query.list();
        
        
        HibernateUtil.closeSession();
        return list;
    }
    /**
     * 7. 条件查询绑定任意类型的参数:占位符
     * @param string
     * @return
     */
    public static List<Teacher> hqlSetParamXx(String name) {
        Session session=HibernateUtil.getSession();
        //定义hql语句
        String hql="from Teacher where tname like ?";
        
        //创建Query查询接口对象
        Query query=session.createQuery(hql);
        String str="%"+name+"%";
        
        query.setParameter(0, str);
        
        //使用list方法查询所有返回list集合
        List<Teacher> list=query.list();
        
        
        HibernateUtil.closeSession();
        return list;
    }
    
    
    /**
     * 8.条件动态:通过对象属性去给命名参数赋值
     * @param name
     * @return
     */
    public static List<Teacher> hqlSetProte(Teacher teacher) {
        
        Session session=HibernateUtil.getSession();
        //定义hql语句
        StringBuilder hql=new StringBuilder("from Teacher as t where 1=1");
        
        if(teacher.getTname()!=null){
            hql.append(" and t.tname=:tname");
        }
    
        //创建Query查询接口对象
        Query query=session.createQuery(hql.toString());
        query.setProperties(teacher);
        
        //使用list方法查询所有返回list集合
        List<Teacher> list=query.list();
        
        HibernateUtil.closeSession();
        return list;
    }
    /**
     * 9.查询单条数据
     * @return
     */
    public static Teacher hhqlGetTeacher(String name) {
        Session session=HibernateUtil.getSession();
        //定义hql语句
        String hql="from Teacher where tname=:pname";
        
        
        //创建Query查询接口对象
        Query query=session.createQuery(hql.toString());
        query.setParameter("pname", name);
        
        //使用
        Teacher teacher=(Teacher) query.uniqueResult();
        
        HibernateUtil.closeSession();
        return teacher;
    }
    /**
     * 10. 分页查询
     * @param i
     * @param j
     * @return
     */
    public static List<Teacher> hqlPage(int pageSize, int pageNo) {
        Session session=HibernateUtil.getSession();
        
        //1.获取中条数
        //定义中条数的hql语句
        String hqlcount="select count(*) from Teacher";
        Query countQuery=session.createQuery(hqlcount);
        
        //uniqueResult()得到总条数
        Integer totalCount=Integer.parseInt(countQuery.uniqueResult().toString());
        System.out.println("总条数:"+totalCount);
        
        //2.计算总页数
        int totalPage=totalCount%pageSize==0?totalCount/pageSize:totalCount/pageSize+1;
        System.out.println("总页数:"+totalPage);
        
        //3.查询的最大记录数(每页查询几条)
        String hql="from Teacher";
        Query query=session.createQuery(hql);
        
        query.setMaxResults(pageSize);
        
        //4.确定查询查询的起点
        query.setFirstResult((pageNo-1)*pageSize);
        
        //5.查询分页数据
        List<Teacher> list=query.list();
        HibernateUtil.closeSession();
        return list;
    }
}

2.7 在项目的com.test包下创建Test.java类

package com.test;

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

import com.dao.TeacherDao;
import com.entity.Teacher;
import com.util.HibernateUtil;

public class Test {

    public static void main(String[] args) {
//        System.out.println("--------------1.使用list查询所有-----------");
//        List<Teacher> list=TeacherDao.hqlList();
//        for (Teacher teacher : list) {
//            System.out.println(teacher);
//        }
//        System.out.println("--------------2.使用Itertor查询所有-----------");
//        Iterator<Teacher> it=TeacherDao.hqlItertor();
//        Teacher te=null;
//        while (it.hasNext()) {
//            te=it.next();
//            System.out.println(te);
//        }
//        HibernateUtil.closeSession();
//        
//        System.out.println("----------3.条件拼接查询-----------");
//        List<Teacher> iflist=TeacherDao.hqlIf("holly");
//        for (Teacher teacher : iflist) {
//            System.out.println(teacher);
//        }
//        
//        System.out.println("----------4.条件查询模糊查询:按照参数位置-----------");
//        List<Teacher> likelist=TeacherDao.hqlLike("holly");
//        for (Teacher teacher : likelist) {
//            System.out.println(teacher);
//        }
//        System.out.println("----------5.条件查询模糊查询:按照名称-----------");
//        List<Teacher> likeNamelist=TeacherDao.hqlLikeName("holly");
//        for (Teacher teacher : likeNamelist) {
//            System.out.println(teacher);
//        }
        
//        System.out.println("----------6.条件查询绑定任意类型的参数-----------");
//        List<Teacher> SetParamlist=TeacherDao.hqlSetParam("holly");
//        for (Teacher teacher : SetParamlist) {
//            System.out.println(teacher);
//        }
//        System.out.println("----------7.条件查询绑定任意类型的参数:占位符-----------");
//        List<Teacher> SetParamXx=TeacherDao.hqlSetParamXx("holly");
//        for (Teacher teacher : SetParamXx) {
//            System.out.println(teacher);
//        }
        System.out.println("----------8.条件动态:命名参数-----------");
//        Teacher te=new Teacher("holly");
//        List<Teacher> SetProte=TeacherDao.hqlSetProte(te);
//        for (Teacher teacher : SetProte) {
//            System.out.println(teacher);
//        }
        
        System.out.println("------------9.查询单条数据-----------");
//        Teacher teacher=TeacherDao.hhqlGetTeacher("holly");
//        System.out.println(teacher);
        
        System.out.println("---------10.分页查询------------");
        List<Teacher> list=TeacherDao.hqlPage(2,2);
        System.out.println("页面大小:"+2+",当前页:"+2);
        for (Teacher teacher : list) {
            System.out.println(teacher);
        }
        
        
        
    }

}

2.8  效果自己试试就知道