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;