Hibernate使用Map实现多对多映射

数据库结构：

create table team2(id varchar(50) primary key,name varchar(50));
create table member2(id varchar(50) primary key,name varchar(50),age varchar(50));
create table memberAtTeams2(member varchar(50),team varchar(50),teamRoles varchar(50));

实体对象：

package mapmanytomany;

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

public class Team ...{
   private String id;
   private String name;
   private Map members=new HashMap();
public String getId() ...{
    return id;
}
public void setId(String id) ...{
    this.id = id;
}


public Map getMembers() ...{
    return members;
}
public void setMembers(Map members) ...{
    this.members = members;
}
public String getName() ...{
    return name;
}
public void setName(String name) ...{
    this.name = name;
}
}


package mapmanytomany;

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

public class Member ...{
   private String id;
   private String name;
   private String teamRole;
   private Map team=new HashMap();
   private String age;
public String getAge() ...{
    return age;
}
public void setAge(String age) ...{
    this.age = age;
}

public String getName() ...{
    return name;
}
public void setName(String name) ...{
    this.name = name;
}


public String getTeamRole() ...{
    return teamRole;
}
public void setTeamRole(String teamRole) ...{
    this.teamRole = teamRole;
}
public String getId() ...{
    return id;
}
public void setId(String id) ...{
    this.id = id;
}
public Map getTeam() ...{
    return team;
}
public void setTeam(Map team) ...{
    this.team = team;
}



}

 
映射:

 

<?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 package="mapmanytomany">
    <class name="Team" table="team2">
       <id name="id" column="id">
         <generator class="uuid.hex"></generator>
       </id>
       <property name="name" column="name"/>
       <map name="members" table="memberAtTeams2" cascade="save-update">
          <key column="team"/>
          <index type="string" column="teamRoles"/>
          <many-to-many class="Member" column="member"></many-to-many>
       </map>
    </class>
</hibernate-mapping>


<?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 package="mapmanytomany">
   
    
      <class name="Member" table="member2">
       <id name="id" column="id">
         <generator class="uuid.hex"></generator>
       </id>
       <property name="name" column="name"/>
       <property name="age" column="age"/>
       <map name="team" table="memberAtTeams2" inverse="true">
          <key column="member"/>
          <index type="string" column="teamRoles"></index>
          <many-to-many class="Team" column="team"></many-to-many>
       </map>
    </class>
</hibernate-mapping>

测试代码：

 

    public static void main(String[] args) ...{
        Configuration cfg=new Configuration();
        cfg.configure();
        SessionFactory sf=cfg.buildSessionFactory();
        Session session=sf.openSession();
        Transaction t=session.beginTransaction();

        Team team1=new Team();
        team1.setName("足球队-01");
        Team team2=new Team();
        team2.setName("足球队-02");
        
        Member m1=new Member();
        m1.setName("张三");
        m1.setAge("11");
        m1.getTeam().put("主力守门员", team1);
        m1.getTeam().put("候选守门员", team2);
        
        Member m2=new Member();
        m2.setName("张四");
        m2.setAge("22");
        m2.getTeam().put("主力中后卫", team1);
        m2.getTeam().put("候选中后卫", team2);
        
        team1.getMembers().put("主力守门员", m1);
        team1.getMembers().put("主力中后卫", m2);
        team2.getMembers().put("候选守门员", m1);
        team2.getMembers().put("候选中后卫", m2);

            session.save(team1);
            session.save(team2);
        t.commit();
        System.out.println("success");

    }

运行结果：

Hibernate: insert into team2 (name, id) values (?, ?)
Hibernate: insert into member2 (name, age, id) values (?, ?, ?)
Hibernate: insert into member2 (name, age, id) values (?, ?, ?)
Hibernate: insert into team2 (name, id) values (?, ?)
Hibernate: insert into memberAtTeams2 (team, teamRoles, member) values (?, ?, ?)
Hibernate: insert into memberAtTeams2 (team, teamRoles, member) values (?, ?, ?)
Hibernate: insert into memberAtTeams2 (team, teamRoles, member) values (?, ?, ?)
Hibernate: insert into memberAtTeams2 (team, teamRoles, member) values (?, ?, ?)

 

可以看到，新增数据和关系都已经建立好了，在HBM文件中，需要注意的是，在两端的Map标签中，都要描述

<index type="string" column="teamRoles"/> 才能正确写入teamRoles值