Hibernate的QBC查询

Customer.java

public class Customer {
    
    public Customer() {
        super();
        // TODO Auto-generated constructor stub
    }
    
    public Customer(String cust_name, String cust_source) {
        super();
        this.cust_name = cust_name;
        this.cust_source = cust_source;
    }

    private Long cust_id;
    private String cust_name;
    private String cust_source;
    private String cust_industry;
    private String cust_level;
    private String cust_phone;
    private String cust_mobile;
    //通过 ORM方式表示：一个客户对应的多个联系人
    //防止的多的一方的集合。Hibernate默认使用的是Set集合
    private Set<LinkMan> linkMans=new HashSet<LinkMan>();
    //省略get和set方法
}

LinkMan.java

public class LinkMan {
    private Long lkm_id;
    private String lkm_name;
    private String lkm_gender;
    private String lkm_phone;
    private String lkm_mobile;
    private String lkm_email;
    private String lkm_qq;
    private String lkm_position;
    private String lkm_memo;
    //通过ORM方式表示：一个联系人只能属于一个客户
    //放置的是一的一方的对象
    private Customer customer;
    //省略了get和set方法
}

Customer.hbm.xml

<?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="com.hibernate.domain.Customer" table="cst_customer">
        <!-- 建立OID与主键映射 -->
        <id name="cust_id" column="cust_id">
            <generator class="native"/>
        </id>
        <!-- 建立普通属性和表的字段的对应 -->
        <property name="cust_name" column="cust_name"/>
        <property name="cust_source" column="cust_source"/>
        <property name="cust_industry" column="cust_industry"/>
        <property name="cust_level" column="cust_level"/>
        <property name="cust_phone" column="cust_phone"/>
        <property name="cust_mobile" column="cust_mobile"/>
        <!-- 配置一对多的映射：放置的多的一方的集合 -->
        <!-- 
            set标签
                * name  ：多的一方的对象集合的属性名称
                * cascade:级联
                * inverse:放弃`外键`维护权    默认false:不放弃
         -->
        <set name="linkMans">
            <!-- 
                key标签
                    * column:多的一方的外键的名称
             -->
            <key column="lkm_cust_id"/>
            <!-- 
                one-to-many标签
                    * class :多的一方的全路径
             -->
            <one-to-many class="com.hibernate.domain.LinkMan"/>
        </set>
    </class>
</hibernate-mapping>

LinkMan.hbm.xml

<?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="com.hibernate.domain.LinkMan" table="cst_linkman">
        <!-- 建立OID与主键映射 -->
        <id name="lkm_id" column="lkm_id">
            <generator class="native"/>
        </id>
        <!-- 建立普通属性与表字段映射 -->
        <property name="lkm_name"/>
        <property name="lkm_gender"/>
        <property name="lkm_phone"/>
        <property name="lkm_mobile"/>
        <property name="lkm_email"/>
        <property name="lkm_qq"/>
        <property name="lkm_position"/>
        <property name="lkm_memo"/>
        <!-- 配置多对一的关系：放置的是一的一方的对象 -->
        <!-- 
            many-to-one标签
                * name      :一的一方的对象的属性名称
                * class     :一的一方的全路径
                * column    ：在多的一方的表的外键的名称
         -->
         <many-to-one name="customer" cascade="save-update,delete" class="com.hibernate.domain.Customer" column="lkm_cust_id"/>
    </class>
</hibernate-mapping>

HibernateUtils.java

public class HibernateUtils {

  public static final Configuration cfg;
  public static final SessionFactory sf;
  
  static{
    cfg = new Configuration().configure();
    sf = cfg.buildSessionFactory();
  }
  
  public static Session openSession(){
    return sf.openSession();
  }
  
  public static Session getCurrentSession() {
    return sf.getCurrentSession();//需要配置
  }
}

src下的hibernate.cfg.xml

<?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>
    <!-- 连接数据库的基本参数 -->
    <!-- hibernate-release-5.0.7.Final\project\etc\hibernate.properties -->
    <!-- localhost:3306 -->
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql:///hibernate_day04</property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.connection.password">password</property>
    <!-- 配置Hibernate的方言 -->
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    
    <!-- ==========可选配置========= -->
    <!-- 打印sql -->
    <property name="hibernate.show_sql">true</property>
    <!-- 格式化sql -->
    <property name="hibernate.format_sql">true</property>
    <!-- 自动建表create update -->
    <property name="hibernate.hbm2ddl.auto">update</property>
    
    <!-- 设置事务隔离级别 -->
    <!-- 
      1 read uncommitted  :脏读、不可重复读、虚读都会发生
      2 read committed    :解决脏读  (oracle默认)
      4 repeatable read   :解决脏读和不可重复读(mysql默认)
      8 serializable      :解决所有问题。串行执行、效率低
     -->
    <property name="hibernate.connection.isolation">4</property>
    <!-- 配置当前线程绑定的Session -->
    <!-- 不用session.close() -->
    <property name="hibernate.current_session_context_class">thread</property>
    
    <!-- 引入映射 -->
    <mapping resource="com/hibernate/domain/Customer.hbm.xml"/>
    <mapping resource="com/hibernate/domain/LinkMan.hbm.xml"/>
    
  </session-factory>
</hibernate-configuration>

测试类

import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.criterion.DetachedCriteria;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;
import org.junit.Test;

import com.hibernate.domain.Customer;
import com.hibernate.domain.LinkMan;
import com.hibernate.utils.HibernateUtils;

/**
 * QBC的查询
 * @author zhang
 *
 */
public class HibernateDemo2 {

  @Test
  /**
   * 简单的查询
   */
  public void demo1() {
    Session session=HibernateUtils.getCurrentSession();
    Transaction tx=session.beginTransaction();
    
    //获得Criteria的对象
    Criteria criteria = session.createCriteria(Customer.class);
    List<Customer> list=criteria.list();
    
    for (Customer customer : list) {
      System.out.println(customer);
    }
    tx.commit();
  }
  
  @Test
  /**
   * 排序查询
   */
  public void demo2() {
    Session session=HibernateUtils.getCurrentSession();
    Transaction tx=session.beginTransaction();
    
    //排序查询
    Criteria criteria = session.createCriteria(Customer.class);
//    criteria.addOrder(Order.asc("cust_id"));//升序
    criteria.addOrder(Order.desc("cust_id"));
    List<Customer> list=criteria.list();
    
    for (Customer customer : list) {
      System.out.println(customer);
    }
    
    tx.commit();
  }
  
  @Test
  /**
   * 分页查询
   */
  public void demo3() {
    Session session=HibernateUtils.getCurrentSession();
    Transaction tx=session.beginTransaction();
    
    //分页查询
    Criteria criteria = session.createCriteria(LinkMan.class);
    criteria.setFirstResult(10);
    criteria.setMaxResults(10);
    List<LinkMan> list = criteria.list();
    
    for (LinkMan linkMan : list) {
      System.out.println(linkMan);
    }
    tx.commit();
  }
  
  @Test
  /**
   * 条件查询
   */
  public void demo4() {
    Session session=HibernateUtils.getCurrentSession();
    Transaction tx=session.beginTransaction();
    
    //条件查询
    Criteria criteria = session.createCriteria(Customer.class);
    //设置条件
    /**
     *  ==  eq
     *  >   gt
     *  >=  ge
     *  <   lt
     *  <=  le
     *  <>  ne
     *  like
     *  in
     *  and
     *  or
     */
    criteria.add(Restrictions.eq("cust_source", "计算机"));
//    criteria.add(Restrictions.or(Restrictions.like("cust_name", "李%")));
    criteria.add(Restrictions.like("cust_name", "李%"));//两个条件并列
    List<Customer> list = criteria.list();
    for (Customer customer : list) {
      System.out.println(customer);
    }
    tx.commit();
  }
  
  @Test
  //统计查询
  public void demo5() {
    Session session=HibernateUtils.getCurrentSession();
    Transaction tx=session.beginTransaction();
    
    Criteria criteria = session.createCriteria(Customer.class);
    /**
     * add        :普通的条件，where后面条件
     * addOrder     :排序
     * setProjection  :聚合函数和group by having
     */
    criteria.setProjection(Projections.rowCount());
//    Object object = criteria.uniqueResult();
    Long num=(Long) criteria.uniqueResult();
    System.out.println(num);
    tx.commit();
  }
  
  @Test
  /**
   * 离线条件查询
   */
  public void demo6() {
        //web层
    DetachedCriteria detachedCriteria=DetachedCriteria.forClass(Customer.class);
    detachedCriteria.add(Restrictions.like("cust_name", "李%"));
    

        //dao层
    Session session=HibernateUtils.getCurrentSession();
    Transaction transaction=session.beginTransaction();
    
    Criteria criteria = detachedCriteria.getExecutableCriteria(session);
    List<Customer> list = criteria.list();
    for (Customer customer : list) {
      System.out.println(customer);
    }
    
    transaction.commit();
  }
}

感觉这个查询的话，和SQL差距比较大，更偏向与面向对象。