java提供了3種集合類：
Set:集合中的元素不須要排序且沒有重復(fù)對象時用
List:當(dāng)集合中允許有重復(fù)對象且需要按索引位置存取時用
Map:集合中需要使用鍵值存取對象時用
數(shù)據(jù)表：items picture tips videos
items:
id int(4) <pk>
itemno varchar(20)
itemname varchar(20)

picture表：
item_id int(4) <pk,fk>
keyname varchar(20) <pk>
picture varchar(100)

tips表：
item_id int(4) <pk,fk>
position int(4) <pk>
tip varchar(200)

videos表：
item_id int(4) <pk,fk>
video varchar(200) <pk>

持久化類：
public class Items implements Serializable{
    private Integer id;
    private String itemno;
    private String itemname;
    private Map picture=new HashMap();
    private List tips=new ArrayList();
    private Set videos=new HashSet();
    public Items(){
    }
}

hbm.xml
<hibernate-mapping package="com.lhb.vo">
    <class name="Items" table="items">
        <id name="id" column="id" type="integer">
            <generator class="native"/>
        </id>
        <property name="itemno" column="itemno" type="string"/>
        <property name="itemname" column="itemname" type="string"/>
        <map name="picture" table="picture" lazy="false">
            <key column="item_id'/>
            <!--指定一個代表鍵對象的字段名-->
            <index column="keyname" type="string"/>
            <!--指定一個與集合元素所對應(yīng)的表字段名-->
            <element column="picture" type="string"/>
       </map>
        <list name="tips" table="tips" lazy="false">
            <key column="item_id"/>
            <!--指定個代表索引位置的字段名-->
            <index column="position" />
            <element column="tip" type="string"/>
        </list>
        <set name="videos' table="videos"  lazy="false">
            <key column="item_id"/>
            <element column="video" type="string" not-null="true"/>
        </set>
    </class>
</hibernate-mapping>