Hibernate集合排序之数据库排序

使用order-by属性，我们可以通过hbm文件执行生成的SQL如何使用order by 查询子句以返回排序后的结果集

数据库结构：

 

create table teamOrder (id varchar(32),teamname varchar(32));
create table studentOrder (id varchar(32),name varchar(32),description varchar(32),team_id varchar(32));
insert into teamOrder values("1","team1");
insert into studentOrder values("1","a","a","1");
insert into studentOrder values("2","b","b","1");
insert into studentOrder values("3","c","c","1");

 

pojo:

 

package Collection.Order;

import java.util.Set;

public class Team ...{
   private String id;
   private String teamname;
   private Set students;
public String getId() ...{
    return id;
}
public void setId(String id) ...{
    this.id = id;
}
public String getTeamname() ...{
    return teamname;
}
public void setTeamname(String teamname) ...{
    this.teamname = teamname;
}
public Set getStudents() ...{
    return students;
}
public void setStudents(Set students) ...{
    this.students = students;
}

}



package Collection.Order;

public class Student ...{
  private String id;
  private String name;
  private String description;
  private Team team;
public String getId() ...{
    return id;
}
public void setId(String id) ...{
    this.id = id;
}
public String getName() ...{
    return name;
}
public void setName(String name) ...{
    this.name = name;
}
public String getDescription() ...{
    return description;
}
public void setDescription(String description) ...{
    this.description = description;
}

public Team getTeam() ...{
    return team;
}
public void setTeam(Team team) ...{
    this.team = team;
}
}

 

Hibernate.cfg.xml

 

<?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">

<!-- Generated by MyEclipse Hibernate Tools.                   -->
<hibernate-configuration>

<session-factory>
    <property name="connection.username">root</property>
    <property name="connection.url">
        jdbc:mysql://localhost:3306/schoolproject?characterEncoding=gb2312&amp;useUnicode=true
    </property>
    <property name="dialect">
        org.hibernate.dialect.MySQLDialect
    </property>
    <property name="myeclipse.connection.profile">mysql</property>
    <property name="connection.password">1234</property>
    <property name="connection.driver_class">
        com.mysql.jdbc.Driver
    </property>
    <property name="hibernate.dialect">
        org.hibernate.dialect.MySQLDialect
    </property>
    <property name="hibernate.show_sql">true</property>
    <property name="current_session_context_class">thread</property>
    <property name="jdbc.batch_size">15</property>
    <mapping resource="Collection/Order/Student.hbm.xml" />
    <mapping resource="Collection/Order/Team.hbm.xml" />




</session-factory>

</hibernate-configuration>

Student.hbm.xml

 

<?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">
<!-- 
    Mapping file autogenerated by MyEclipse - Hibernate Tools
-->
<hibernate-mapping>
<class name="Collection.Order.Student" table="studentOrder" >
    <id name="id" unsaved-value="null">
      <generator class="uuid.hex"></generator>
    </id>
  
    <property name="name" type="string" column="name"></property>
   
    <property name="description" type="string" column="description"></property> 
    <many-to-one name="team" 
                 column="team_id"
                 class="Collection.Order.Team" 
                 cascade="none" 
                 fetch="join">
    </many-to-one>
</class>

</hibernate-mapping>

Team.hbm.xml

 

 

<?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">
<!-- 
    Mapping file autogenerated by MyEclipse - Hibernate Tools
-->
<hibernate-mapping>
<class name="Collection.Order.Team" table="teamOrder" >
    <id name="id" unsaved-value="null">
      <generator class="uuid.hex"></generator>
    </id>
    <property name="teamname" type="string" column="teamname"></property>
    <!-- 以名称降序返回student集合 -->
    <set name="students" table="studentOrder" cascade="all" order-by="name desc">
      <key column="team_id"></key>
      <one-to-many class="Collection.Order.Student"/>
    </set>
</class>

</hibernate-mapping>

 

测试代码：

 

package Collection.Order;


import java.io.File;
import java.util.Iterator;
import java.util.Set;

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

public class Test ...{


    public static void main(String[] args) ...{

        String filePath=System.getProperty("user.dir")+File.separator+"src/Collection/Order"+File.separator+"hibernate.cfg.xml";
        File file=new File(filePath);
        System.out.println(filePath);
        SessionFactory sessionFactory=new Configuration().configure(file).buildSessionFactory();
        Session session=sessionFactory.openSession();
        Transaction t=session.beginTransaction();
        
        Team team=(Team)session.createQuery("from Team t where t.teamname='team1'").uniqueResult();
        Set result=team.getStudents();
        for (Iterator iterator = result.iterator(); iterator.hasNext();) ...{
            Student object = (Student) iterator.next();
            System.out.println(object.getName());
        }
        
        t.commit();
        
    }

}

 

测试结果：

Hibernate: select team0_.id as id1_, team0_.teamname as teamname1_ from teamOrder team0_ where team0_.teamname='team1'
Hibernate: select students0_.team_id as team4_1_, students0_.id as id1_, students0_.id as id0_0_, students0_.name as name0_0_, students0_.description as descript3_0_0_, students0_.team_id as team4_0_0_ from studentOrder students0_ where students0_.team_id=? order by students0_.name desc
c
b
a