Hibernate 多对多双向关联

  
  
一、模型介绍 
  
多个人（Person ）对应多个地址（Address ）。
一个人可对应多个地址，一个地址也可以对应多个人。 
  
二、实体（省略getter 、setter 方法） 
  
public class Personnn_sx { 
    private int personid; 
    private String name; 
    private int age; 
    private Set addresses=new HashSet(); 
  
public class Addressnn_sx { 
    private int addressid; 
    private String addressdetail; 
    private Set persons = new HashSet(); 
  
三、表模型 
  
mysql> desc person_nn_sx; 
+----------+--------------+------+-----+---------+----------------+ 
| Field    | Type         | Null | Key | Default | Extra          | 
+----------+--------------+------+-----+---------+----------------+ 
| personid | int(11)      | NO   | PRI | NULL    | auto_increment | 
| name     | varchar(255) | YES  |     | NULL    |                | 
| age      | int(11)      | YES  |     | NULL    |                | 
+----------+--------------+------+-----+---------+----------------+ 
  
mysql> desc address_nn_sx; 
+---------------+--------------+------+-----+---------+----------------+ 
| Field         | Type         | Null | Key | Default | Extra          | 
+---------------+--------------+------+-----+---------+----------------+ 
| addressid     | int(11)      | NO   | PRI | NULL    | auto_increment | 
| addressdetail | varchar(255) | YES  |     | NULL    |                | 
+---------------+--------------+------+-----+---------+----------------+ 
  
mysql> desc join_nn_sx; 
+-----------+---------+------+-----+---------+-------+ 
| Field     | Type    | Null | Key | Default | Extra | 
+-----------+---------+------+-----+---------+-------+ 
| addressid | int(11) | NO   | PRI |         |       | 
| personid  | int(11) | NO   | PRI |         |       | 
+-----------+---------+------+-----+---------+-------+ 
  
四、生成的SQL 脚本 
  
/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */ 
CREATE TABLE `address_nn_sx` ( 
  `addressid` int(11) NOT NULL auto_increment, 
  `addressdetail` varchar(255) default NULL, 
  PRIMARY KEY  (`addressid`) 
) ENGINE=InnoDB DEFAULT CHARSET=gbk; 
  
/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */ 
CREATE TABLE `person_nn_sx` ( 
  `personid` int(11) NOT NULL auto_increment, 
  `name` varchar(255) default NULL, 
  `age` int(11) default NULL, 
  PRIMARY KEY  (`personid`) 
) ENGINE=InnoDB DEFAULT CHARSET=gbk; 
  
/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */ 
CREATE TABLE `join_nn_sx` ( 
  `addressid` int(11) NOT NULL, 
  `personid` int(11) NOT NULL, 
  PRIMARY KEY  (`personid`,`addressid`), 
  KEY `FK6EBBC5EF6C600921` (`personid`), 
  KEY `FK6EBBC5EF2A92FF3D` (`addressid`), 
  CONSTRAINT `FK6EBBC5EF2A92FF3D` FOREIGN KEY (`addressid`) REFERENCES `address_nn_sx` (`addressid`), 
  CONSTRAINT `FK6EBBC5EF6C600921` FOREIGN KEY (`personid`) REFERENCES `person_nn_sx` (`personid`) 
) ENGINE=InnoDB DEFAULT CHARSET=gbk; 
  
五、映射方法 
  
<hibernate-mapping> 
    <class name="com.lavasoft.sx._n_n.Personnn_sx" table="PERSON_nn_sx"> 
        <id name="personid"> 
            <generator class="identity"/> 
        </id> 
        <property name="name"/> 
        <property name="age"/> 
        <!-- 映射集合属性，关联到持久化类--> 
         <!--table="join_1ntab_sx" 指定了连接表的名字--> 
        <set name="addresses" 
             table="join_nn_sx" 
             cascade="all"> 
            <!--column="personid" 指定连接表中关联当前实体类的列名--> 
            <key column="personid" not-null="true"/> 
            <!--column="addressid" 是连接表中关联本实体的外键--> 
            <many-to-many column="addressid" 
                          class="com.lavasoft.sx._n_n.Addressnn_sx"/> 
        </set> 
    </class> 
</hibernate-mapping> 
  
<hibernate-mapping> 
    <class name="com.lavasoft.sx._n_n.Addressnn_sx" 
           table="ADDRESS_nn_sx"> 
        <id name="addressid"> 
            <generator class="identity"/> 
        </id> 
        <property name="addressdetail"/> 
         <!--table="join_nn_sx" 是双向多对多的连接表--> 
        <set name="persons" 
             inverse="true" 
             table="join_nn_sx"> 
            <!--column="addressid" 是连接表中关联本实体的外键--> 
            <key column="addressid"/> 
            <many-to-many column="personid" 
                          class="com.lavasoft.sx._n_n.Personnn_sx"/> 
        </set> 
    </class> 
</hibernate-mapping> 
  
六、测试方法 
  
public class Test_nn_sx { 
    public static void main(String[] args){ 
        Addressnn_sx add1=new Addressnn_sx(); 
        Addressnn_sx add2=new Addressnn_sx(); 
        Personnn_sx p1=new Personnn_sx(); 
        Personnn_sx p2=new Personnn_sx(); 
  
        add1.setAddressdetail(" 郑州市经三路"); 
        add2.setAddressdetail(" 合肥市宿州路"); 
        p1.setName("wang"); 
        p1.setAge(30); 
        p2.setName("zhang"); 
        p2.setAge(22); 
  
        p1.getAddresses().add(add1); 
        p1.getAddresses().add(add2); 
        p2.getAddresses().add(add2); 
        add1.getPersons().add(p1); 
        add2.getPersons().add(p1); 
        add2.getPersons().add(p2); 
  
  
        Session session= HibernateUtil.getCurrentSession(); 
        Transaction tx=session.beginTransaction(); 
        session.save(p1); 
        session.save(p2); 
//        session.saveOrUpdate(add1); 
//        session.saveOrUpdate(add2); 
        tx.commit(); 
        HibernateUtil.closeSession(); 
    } 
} 
  
七、测试结果 
  
1) : 正常保存. 
        session.save(p1); 
        session.save(p2); 
//        session.saveOrUpdate(add1); 
//        session.saveOrUpdate(add2); 
  
  Hibernate: insert into PERSON_nn_sx (name, age) values (?, ? ) 
  Hibernate: insert into ADDRESS_nn_sx (addressdetail) values (?) 
  Hibernate: insert into ADDRESS_nn_sx (addressdetail) values (?) 
  Hibernate: insert into PERSON_nn_sx (name, age) values (?, ? ) 
  Hibernate: insert into join_nn_sx (personid, addressid) values (?, ? ) 
  Hibernate: insert into join_nn_sx (personid, addressid) values (?, ? ) 
  Hibernate: insert into join_nn_sx (personid, addressid) values (?, ? ) 

 
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