Hibernate查询示例

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1.db.sql

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drop database sun;  
create database sun;  
use sun;  
drop table CUSTOMERS;  
create table CUSTOMERS (  
   ID int  primary key,  
   NAME varchar(15),  
   AGE int  
);  
drop table ORDERS;  
create table ORDERS (  
   ID int  primary key,  
   ORDER_NUMBER varchar(15),  
   PRICE DECIMAL(10,2),  
   CUSTOMER_ID int,  
   foreign key (CUSTOMER_ID) references CUSTOMERS(ID)  
);  
insert into CUSTOMERS(ID,NAME,AGE) values(1,'Tom',21);  
insert into CUSTOMERS(ID,NAME,AGE) values(2,'Mike',24);  
insert into CUSTOMERS(ID,NAME,AGE) values(3,'Jack',30);  
insert into CUSTOMERS(ID,NAME,AGE) values(4,'Linda',25);  
insert into CUSTOMERS(ID,NAME,AGE) values(5,'Tom',25);  
  
insert into ORDERS(ID,ORDER_NUMBER,PRICE,CUSTOMER_ID) values(1,'Tom_Order001',100,1);  
insert into ORDERS(ID,ORDER_NUMBER,PRICE,CUSTOMER_ID) values(2,'Tom_Order002',200,1);  
insert into ORDERS(ID,ORDER_NUMBER,PRICE,CUSTOMER_ID) values(3,'Tom_Order003',300,1);  
insert into ORDERS(ID,ORDER_NUMBER,PRICE,CUSTOMER_ID) values(4,'Mike_Order001',100,2);  
insert into ORDERS(ID,ORDER_NUMBER,PRICE,CUSTOMER_ID) values(5,'Jack_Order001',200,3);  
insert into ORDERS(ID,ORDER_NUMBER,PRICE,CUSTOMER_ID) values(6,'Linda_Order001',100,4);  
insert into ORDERS(ID,ORDER_NUMBER,PRICE,CUSTOMER_ID) values(7,'UnknownOrder',200,null);  

2.搭建开发环境

使用的是Hibernate3.2

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<?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>  
        <!-- 最大连接数 -->  
        <property name="c3p0.max_size">10</property>  
        <!-- 最小连接数 -->  
        <property name="c3p0.min_size">3</property>  
        <!-- 超时时间 单位 秒-->  
        <property name="c3p0.timeout">300</property>  
         <!-- 被缓存的PreparedStatement实例的最大数目 -->  
        <property name="c3p0.max_statements">5</property>  
        <!-- 连接的URL -->  
        <property name="connection.url">jdbc:mysql://localhost:3306/sun</property>  
        <!-- 用户名 -->  
        <property name="connection.username">root</property>  
        <!-- 密码 -->  
        <property name="connection.password">root</property>  
        <!-- 驱动-->  
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>  
        <!-- 数据库方言 -->  
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>  
        <!-- 显示SQL语句 -->  
        <property name="show_sql">true</property>  
        <!-- 格式化SQL语句 -->  
        <property name="format_sql">true</property>  
        <!-- 映射文件的地址 -->  
        <mapping resource="org/cdl/domain/Customers.hbm.xml" />  
        <mapping resource="org/cdl/domain/Orders.hbm.xml" />  
    </session-factory>  
</hibernate-configuration>  

3.HibernateUtil（Hibernate工具类）

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package org.cdl.util;  
import org.hibernate.Session;  
import org.hibernate.SessionFactory;  
import org.hibernate.cfg.Configuration;  
public class HibernateUtil {  
      
    /** 
     * 初始化hibernate.cfg.xml文件 
     */  
    private static SessionFactory sf = null;  
    static {  
        Configuration cfg = new Configuration().configure();  
        sf = cfg.buildSessionFactory();  
    }  
    /** 
     * 获取Session对象 
     * @return 获取到的Session对象 
     */  
    public static Session getSession() {  
        return sf.openSession();  
    }  
    /** 
     * 关闭Session对象 
     * @param session 要关闭的Session对象 
     */  
    public static void closeSession(Session session) {  
        if (session != null) {  
            session.close();  
        }  
    }  
}  

4.测试代码

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package org.cdl.test;  
import java.util.Iterator;  
import java.util.List;  
import java.util.Set;  
import org.cdl.domain.Customers;  
import org.cdl.domain.Orders;  
import org.cdl.util.HibernateUtil;  
import org.hibernate.Criteria;  
import org.hibernate.Query;  
import org.hibernate.SQLQuery;  
import org.hibernate.Session;  
import org.hibernate.criterion.Example;  
import org.hibernate.criterion.Restrictions;  
public class Demo01 {  
    public static void main(String[] args) {  
        /** 
         * HQL 
         */  
        String hql="from Customers as c where c.name=? and c.age=?";  
        Object []params={"Tom",21};  
        show(findByHQL(hql,params));  
          
        /** 
         * QBC 
         */  
        show(findByQBC());  
          
        /** 
         * QBE 
         */  
        show(findByQBE());  
          
        /** 
         * SQL 
         */  
        String sql="select * from customers where name like ? and age=?";  
        Object[] values={"Tom",21};  
        show(findBySQL(sql, values));  
    }  
      
    //HQL检索方式  
    public static List findByHQL(String hql,Object[]params){  
        Session session=HibernateUtil.getSession();  
        Query query=session.createQuery(hql);  
        if(params!=null){  
            for(int i=0;i<params.length;i++){  
                query.setParameter(i, params[i]);  
            }  
        }  
        //HibernateUtil.closeSession(session);  
        return query.list();  
    }    
      
    //QBC的检索方式  
    public static List findByQBC(){  
        Session session=HibernateUtil.getSession();  
        Criteria c=session.createCriteria(Customers.class);  
        c.add(Restrictions.like("name","T%"));  
        c.add(Restrictions.eq("age", 21));  
        //HibernateUtil.closeSession(session);  
        return c.list();  
          
    }  
      
    //QBE的检索方式  
    public static List findByQBE(){  
        Session session=HibernateUtil.getSession();  
        Criteria c=session.createCriteria(Customers.class);  
        Customers entity=new Customers();  
        entity.setAge(21);  
        entity.setName("Tom");  
        c.add(Example.create(entity));  
        //HibernateUtil.closeSession(session);  
        return c.list();  
    }  
      
    //本地SQL  
    public static List findBySQL(String sql,Object[]params){  
        Session session=HibernateUtil.getSession();  
        SQLQuery query=session.createSQLQuery(sql);  
        query.addEntity(Customers.class);    
        if(params!=null){  
            for(int i=0;i<params.length;i++){  
                query.setParameter(i, params[i]);  
            }  
        }  
        //HibernateUtil.closeSession(session);  
        return query.list();  
    }  
      
    //遍历结果集  
    public static void show(List list){  
        if(list.size()>0){  
            Iterator it=list.iterator();  
            while(it.hasNext()){  
                Customers c=(Customers)it.next();  
                System.out.println(c.getId()+" "+c.getName()+" "+c.getAge());  
                if(c.getOrderses().size()>0){  
                    Set set=c.getOrderses();  
                    Iterator it2=set.iterator();  
                    while(it2.hasNext()){  
                        Orders o=(Orders)it2.next();  
                        System.out.println("...."+o.getId()+" "+o.getOrderNumber()+" "+o.getPrice());  
                    }  
                }  
            }  
        }  
    }  
}  

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