Hibernate集合映射之Map-----element映射基本类型值

所谓基本类型，就是指java.lang.String,java.lang.Integer等基本类 以及用户编写的非实体类，虽然map中的数据是我们的数据库中的一个表，但我们不必为他创建POJO类及HBM文件

数据库结构：

 

create table teamMap (id varchar(32),teamname varchar(32));
create table studentMap (name varchar(32),description varchar(32), team_id varchar(32));

 

实体类：（只有Team）,其中的student无实体类，用表studentMap的name字段作为key,description作为value

 

package Collection.Map.Simple;

import java.util.HashMap;
import java.util.Map;

public class Team ...{
   private String id;
   private String teamname;
   private Map students=new HashMap();
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 Map getStudents() ...{
    return students;
}
public void setStudents(Map students) ...{
    this.students = students;
}
}

 

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.Map.Simple.Team" table="teamMap" >
    <id name="id" unsaved-value="null">
      <generator class="uuid.hex"></generator>
    </id>
    <property name="teamname" type="string" column="teamname"></property>
    <map name="students" table="studentMap">
      <key column="team_id"></key>
      <!-- index代表key,element代表value,一个map标签只能有一个element -->
      <index column="name" type="string"></index>
      <element type="string" column="description"></element>
    </map>
</class>

</hibernate-mapping>

 

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/Map/Simple/Team.hbm.xml" />




</session-factory>

</hibernate-configuration>

 

测试代码：

 

package Collection.Map.Simple;


import java.io.File;
import java.util.Map;

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/Map/Simple"+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=new Team();
        team.setTeamname("team1");
        Map stuMap=team.getStudents();
        stuMap.put("stu1", "stu1 description");
        stuMap.put("stu2", "stu2 description");
        
        session.save(team);
        
        t.commit();
        
    }

}

 

运行结果：

Hibernate: insert into teamMap (teamname, id) values (?, ?)
Hibernate: insert into studentMap (team_id, name, description) values (?, ?, ?)
Hibernate: insert into studentMap (team_id, name, description) values (?, ?, ?)