day36-hibernate检索和优化 02-Hibernate检索方式：简单查询及别名查询

Hibernate:
    insert
    into
        Customer
        (cname)
    values
        (?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    insert
    into
        orders
        (addr, cno)
    values
        (?, ?)
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?
Hibernate:
    update
        orders
    set
        cno=?
    where
        oid=?

初始化数据之后使用三种方式检索数据。

客户这里打印也打印出订单的集合，订单这边又打印客户了。这是死循环了，所以这里应该去掉一方的打印。

用SQL的时候给列起过别名。Mysql数据库用As起别名,HQL也是支持这种操作的。

package cn.itcast.test;

import java.util.Arrays;
import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;

import cn.itcast.utils.HibernateUtils;
import cn.itcast.vo.Customer;
import cn.itcast.vo.Order;

/**
 * Hibernate的检索方式
 * @author zhongzh
 *
 */
public class HibernateDemo1 {
   @Test
   /*
    * 使用别名:
    * 
    */
    public void demo3(){
       Session session = HibernateUtils.openSession();
       Transaction tx = session.beginTransaction();
       
       //使用别名
       //List<Customer> list = session.createQuery("from Customer as c where c.cname = ?").list();
/*       List<Customer> list = session.createQuery("from Customer as c").list();
       System.out.println(list);*/
       
       //使用别名:带参数
/*       List<Customer> list = session.createQuery("from Customer as c where c.cname = ?").setString(0, "小沈").list();
       System.out.println(list);*/
       
       //别名as可以省略
/*              List<Customer> list = session.createQuery("from Customer  c").list();
              System.out.println(list);*/
      //不支持 select * from Customer写法.可以写成select 别名  from Customer as 别名;
      //List<Customer> list =  session.createQuery("select * from Customer").list();//createQuery不支持select *的写法,会报语法错误
       List<Customer> list =  session.createQuery("select c from Customer c").list();//createQuery不支持select *的写法,会报语法错误
      
       System.out.println(list);
       tx.commit();
       session.close();
   }
    
@Test
public void demo2(){
    Session session = HibernateUtils.openSession();
    Transaction tx = session.beginTransaction();
    
    //1.使用HQL查询所有客户信息:
/*    Query query =  session.createQuery("from Customer");//"from Customer"是一个HQL语句。返回一个Query接口
    query.list();
    *
    */
    //session.createQuery("from Customer").setString("", "").list();//HQL支持方法链编程
/*    List<Customer> list = session.createQuery("from Customer").list();//HQL支持方法链编程
    for(Customer customer:list){
        System.out.println(customer);
    }*/
    
    //2.使用QBC的方式查询所有记录:
/*    List<Customer>  list=  session.createCriteria(Customer.class).list();//返回Criteria接口
    for (Customer customer:list){
        System.out.println(customer);
    }*/
    
    //3.使用SQL语句查询所有记录:
/*    List<Object[]> list = session.createSQLQuery("select * from customer").list();//这里要写SQL语句 这里操作的是数据库表
    //但是HQL和QBC方式操作的都是对象  这种SQL查询的方式得到的List集合不会直接装到实体对象里面。而是放到Object数组中。
    for(Object[] objects:list){
        System.out.println(Arrays.toString(objects));//把Object数组打印一下
    }*/
    //4.使用SQL语句查询所有记录:封装到实体对象中
    List<Customer> list = session.createSQLQuery("select * from customer").addEntity(Customer.class).list();//这里要写SQL语句 这里操作的是数据库表
    //但是HQL和QBC方式操作的都是对象  这种SQL查询的方式得到的List集合不会直接装到实体对象里面。而是放到Object数组中。这也是方法链编程
    for(Customer customer:list){
        System.out.println(customer);//这个时候就是打印出实体对象的方式
    }
    tx.commit();
    session.close();
}
@Test
/*
 * 
 * 初始化数据
 */
public void demo1(){
  Session session = HibernateUtils.openSession();
  Transaction tx = session.beginTransaction();
  
  Customer customer = new Customer();
  //customer.setCname("小金");
  //customer.setCname("小明");
  customer.setCname("小沈");
  
  for(int i=0;i<=10;i++){
      Order order = new Order();
      //order.setAddr("西三旗"+i);
      order.setAddr("山东"+i);
      order.setCustomer(customer);
      
      customer.getOrders().add(order);
  }
  session.save(customer);
  //还需要设置订单,如果不想设置订单那就要配置级联才行
  tx.commit();
  session.close();
}
}

package cn.itcast.vo;

import java.util.HashSet;
import java.util.Set;

/**
 * 客户的实体:
 * @author 姜涛
 *
 */
public class Customer {
    private Integer cid;
    private String cname;
    // 一个客户有多个订单.
    private Set<Order> orders = new HashSet<Order>();
    public Integer getCid() {
        return cid;
    }
    public void setCid(Integer cid) {
        this.cid = cid;
    }
    public String getCname() {
        return cname;
    }
    public void setCname(String cname) {
        this.cname = cname;
    }
    public Set<Order> getOrders() {
        return orders;
    }
    public void setOrders(Set<Order> orders) {
        this.orders = orders;
    }
    @Override
    public String toString() {//客户这里打印也打印出订单的集合。这是死循环了，所以这里应该去掉一方的打印。
    /*    return "Customer [cid=" + cid + ", cname=" + cname + ", orders="
                + orders + "]";*/
            return "Customer [cid=" + cid + ", cname=" + cname + "]";//客户这里去掉订单集合的打印
        
    }
    
}

package cn.itcast.vo;
/**
 * 订单的实体:
 * @author 姜涛
 *
 */
public class Order {
    private Integer oid;
    private String addr;
    // 订单属于某一个客户.放置一个客户的对象.
    private Customer customer;
    public Integer getOid() {
        return oid;
    }
    public void setOid(Integer oid) {
        this.oid = oid;
    }
    public String getAddr() {
        return addr;
    }
    public void setAddr(String addr) {
        this.addr = addr;
    }
    public Customer getCustomer() {
        return customer;
    }
    public void setCustomer(Customer customer) {
        this.customer = customer;
    }
    @Override
    public String toString() {//订单这边又打印客户了。这是死循环了，所以这里应该去掉一方的打印。
        return "Order [oid=" + oid + ", addr=" + addr + ", customer="
                + customer + "]";
    }
    
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!--  
    <class name="cn.itcast.hibernate3.demo2.Customer" table="customer">
    -->
    <class name="cn.itcast.vo.Customer">
        <!-- 配置唯一标识 -->
        <id name="cid" column="cid">
            <generator class="native"/>
        </id>
        <!-- 配置普通属性 -->
        <property name="cname" column="cname" length="20"/>
        
        <!-- 建立映射 -->
        <!-- 配置一个集合 <set>的name Customer对象中的关联对象的属性名称. -->
        <!-- 这里把级联去掉  要最简短的配置 
        <set name="orders" cascade="save-update" inverse="true">
-->
<set name="orders" cascade="save-update">
            <!-- <key>标签中column:用来描述一对多多的一方的外键的名称. -->
            <key column="cno"></key>
            <!-- 配置一个<one-to-many>标签中class属性:订单的类的全路径 -->
            <!--  
            <one-to-many class="cn.itcast.hibernate3.demo2.Order"/>
            -->
            <one-to-many class="cn.itcast.vo.Order"/>
        </set>
    </class>
</hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!-- 
    <class name="cn.itcast.hibernate3.demo2.Order" table="orders">
    -->
    <class name="cn.itcast.vo.Order" table="orders">
        <!-- 配置唯一标识  -->
        <id name="oid" column="oid">
            <generator class="native"/>
        </id>
        <!-- 配置普通属性 -->
        <property name="addr" column="addr" length="50"/>
        <!-- 配置映射 -->
        <!-- 
        <many-to-one>标签
            name     :关联对象的属性的名称.
            column    :表中的外键名称.
            class    :关联对象类的全路径
        -->
        <!--  
        <many-to-one name="customer" column="cno" class="cn.itcast.hibernate3.demo2.Customer"/>
        -->
        <many-to-one name="customer" column="cno" class="cn.itcast.vo.Customer"/>
    </class>
</hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>
    <!-- 必须去配置的属性 -->
    <!-- 配置数据库连接的基本信息: -->
    <property name="hibernate.connection.driver_class">
        com.mysql.jdbc.Driver
    </property>
    <property name="hibernate.connection.url"><!-- 连接的数据库是hibernate3_day02 -->
        jdbc:mysql:///hibernate3_day03
    </property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.connection.password"></property>
    <!-- Hibernate的方言 -->
    <!-- 生成底层SQL不同的 -->
    <property name="hibernate.dialect">
        org.hibernate.dialect.MySQLDialect
    </property>

    <!-- 可选的属性 -->
    <!-- 显示SQL -->
    <property name="hibernate.show_sql">true</property>
    <!-- 格式化SQL -->
    <property name="hibernate.format_sql">true</property>

    <property name="hibernate.connection.autocommit">false</property>
    <!-- hbm:映射 to DDL: create drop alter -->
    <property name="hibernate.hbm2ddl.auto">update</property>

    <!-- C3P0连接池设定-->
    <!-- 使用c3po连接池  配置连接池提供的供应商-->
    <property name="connection.provider_class">
        org.hibernate.connection.C3P0ConnectionProvider
    </property>

    <!--在连接池中可用的数据库连接的最少数目 -->
    <property name="c3p0.min_size">5</property>
    <!--在连接池中所有数据库连接的最大数目  -->
    <property name="c3p0.max_size">20</property>
    <!--设定数据库连接的过期时间,以秒为单位,
        如果连接池中的某个数据库连接处于空闲状态的时间超过了timeout时间,就会从连接池中清除 -->
    <property name="c3p0.timeout">120</property>
    <!--每3000秒检查所有连接池中的空闲连接 以秒为单位-->
    <property name="c3p0.idle_test_period">3000</property>

    <!-- 通知Hibernate加载那些映射文件 -->
    <!--     <mapping resource="cn/itcast/hibernate3/demo1/Book.hbm.xml" />
        <mapping resource="cn/itcast/hibernate3/demo2/Customer.hbm.xml" />
        <mapping resource="cn/itcast/hibernate3/demo2/Order.hbm.xml" />
        <mapping resource="cn/itcast/hibernate3/demo1/Book.hbm.xml" /> -->
    <!-- 把映射文件中的这几个都拿掉  重新把它引入  -->
    <mapping resource="cn/itcast/vo/Customer.hbm.xml" />
    <mapping resource="cn/itcast/vo/Order.hbm.xml" />


</session-factory>
</hibernate-configuration>

posted on 2017-04-08 19:15 绿茵好莱坞阅读(156) 评论(0) 编辑收藏举报

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day36-hibernate检索和优化 02-Hibernate检索方式：简单查询及别名查询

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