Hibernate学习22 -- 关联映射12 -- 集合映射

在对象中有普通属性，也有可能有集合属性如set、list、array、map，那我们在hibernate中该如何映射呢？我们存储应当如下面显示：

代码实现：

1)        建立一个对象，里面包含普通属性也有集合属性，如list、set、array、map，例如：CollectionMapping.java

public class CollectionMapping {       private int id;       private String name;     private Set setValue;        private List listValue;      private String[] arrayValue;        private Map mapValue;

 

2)        建立映射文件，例如：CollectionMapping.hbm.xml

<hibernate-mapping>     <class name="hibernate.CollectionMapping"                                     table="t_CollectionMapping">        <id name="id">            <generator class="native"/>        </id>        <property name="name"/>        <set name="setValue" table="t_set_value">            <key column="set_id"/>            <element type="string" column="set_value"/>        </set>        <list name="listValue" table="t_list_value">            <key column="list_id"/>            <list-index column="list_index"/>            <element type="string" column="list_value"/>        </list>        <array name="arrayValue" table="t_array_value">            <key column="array_id"/>            <list-index column="array_index"/>            <element type="string" column="array_value"/>        </array>        <map name="mapValue" table="t_map_value">            <key column="map_id"/>            <map-key type="string" column="map_key"/>            <element type="string" column="map_value"/>        </map>     </class> </hibernate-mapping>

 

3)        测试代码：

public class CollectionMappintTest extends TestCase {     public void testSave1() {        Session session = null;        CollectionMapping c = new CollectionMapping();               c.setName("xxx");               Set setValue = new HashSet();        setValue.add("a");        setValue.add("b");        c.setSetValue(setValue);               List listValue = new ArrayList();        listValue.add("c");        listValue.add("d");        c.setListValue(listValue);               String[] arrayValue = new String[]{"e", "f"};        c.setArrayValue(arrayValue);               Map mapValue = new HashMap();        mapValue.put("k1", "v1");        mapValue.put("k2", "v2");        c.setMapValue(mapValue);           try {            session = HibernateUtils.getSession();            session.beginTransaction();            session.save(c);            session.getTransaction().commit();        }catch(Exception e) {            e.printStackTrace();            session.getTransaction().rollback();        }finally {            HibernateUtils.closeSession(session);        }     }       public void testLoad1() {        Session session = null;        try {            session = HibernateUtils.getSession();            session.beginTransaction();            CollectionMapping c = (CollectionMapping)session.load (CollectionMapping.class, 1);            System.out.println("name=" + c.getName());            System.out.println("setvalue=" + c.getSetValue());            System.out.println("mapvalue=" + c.getMapValue());            System.out.println("listvalue=" + c.getListValue());            session.getTransaction().commit();        }catch(Exception e) {            e.printStackTrace();            session.getTransaction().rollback();        }finally {            HibernateUtils.closeSession(session);        }     }          }