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假设有一个实体类,用于存放用户信息,其定义如下:

package events;
import java.util.*;
public class Person {
    private Long id;
    private int age;
    private String firstname;
    private String lastname;
    public Person() {}

    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getFirstname() {
        return firstname;
    }
    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }
    public String getLastname() {
        return lastname;
    }
    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

    private Set emailAddresses = new HashSet();
    public Set getEmailAddresses() {
        return emailAddresses;
    }
    public void setEmailAddresses(Set emailAddresses) {
        this.emailAddresses = emailAddresses;
    }

    private Set events = new HashSet();
    // Defensive, convenience methods
    protected Set getEvents() {
        return events;
    }
    protected void setEvents(Set events) {
        this.events = events;
    }
    public void addToEvent(Event event) {
        this.getEvents().add(event);
        event.getParticipants().add(this);
    }
    public void removeFromEvent(Event event) {
        this.getEvents().remove(event);
        event.getParticipants().remove(this);
    }
}

 
则相应的描述POJO--->Person.hbm.xml中的配置信息如下:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="events.Person" table="PERSON">
        <id name="id" column="PERSON_ID">
            <generator class="identity" />
        </id>
        <property name="age" />
        <property name="firstname" />
        <property name="lastname" />
        <set name="events" table="PERSON_EVENT">
            <key column="PERSON_ID" />
            <many-to-many column="EVENT_ID" class="events.Event" />
        </set>
        <set name="emailAddresses" table="PERSON_EMAIL_ADDR">
            <key column="PERSON_ID" />
            <element type="string" column="EMAIL_ADDR" />
        </set>
    </class>
</hibernate-mapping>


说明:
1.class 节点

name: 类名

table: 类对应表名,默认为类名称

dynamic-update: 生成更新字段时,只包含发生变动的字段,默认为false。

dynamic-insert: 生成insert语句时仅包含非null字段

Proxy: 代理类,默认为空

discriminator-value: 子类辨别标识用于多态支持

where: 通过限定条件查询结果集。如:查询有籍在校学生的信息可以使用"where studentstatus='0'"

2.id节点

1.column               字段名称
2.type                 字段类型
3.length               字段长度
4.unsaved-value        用于判断对象值是否已经保存
5.generator-class      主键产生方式
                       assigned
                       hilo
                       seqhilo
                       increment
                       identity
                       sequence
                       native
                       uuid.hex
                       uuid.string
                       foreign



3.property 节点

1.column               数据库表字段名称
2.type                 类型
3.length               长度
4.not-null             字段是否允许为空
5.unique               字段是否允许唯一(是否允许重复值)
6.insert               insert操作时,是否允许包含本字段数值
7.update               update操作时,是否包含本字段数据





Event.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
 <class name="events.Event" table="EVENTS">
  <id name="id" column="EVENT_ID">
   <generator class="native" />
  </id>
  <property name="date" type="timestamp" column="EVENT_DATE" />
  <property name="title" />
  <set name="participants" table="PERSON_EVENT" inverse="true">
   <key column="EVENT_ID" />
   <many-to-many column="PERSON_ID" class="events.Person" />
  </set>
 </class>
</hibernate-mapping>
posted on 2010-05-11 14:06 Eric_jiang 阅读(751) 评论(0)  编辑  收藏 所属分类: Hibernate

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