Hibernate(三)--关联映射

category.hbm.xml

<?xml version="1.0"?>
<!doctype hibernate-mapping public
        "-//hibernate/hibernate mapping dtd 3.0//en"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.h.pojo">
    <class name="category" table="category_">
        <id name="id" column="id">
            <generator class="native">
            </generator>
        </id>
        <property name="name" />
    </class>

</hibernate-mapping>

product.hbm.xml

<?xml version='1.0' encoding='utf-8'?>
        <!doctype hibernate-mapping public
        "-//hibernate/hibernate mapping dtd 3.0//en"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.h.pojo">
    <class name="product" table="product_">
        <id name="id" column="id">
            <generator class="native"></generator>
        </id>
        <property name="name" />
        <property name="price" />


        <many-to-one name="category" class="category" column="cid"></many-to-one>   product多 对 一category


    </class>
</hibernate-mapping>

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!doctype hibernate-configuration public
        "-//hibernate/hibernate configuration dtd//en"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <!-- database connection settings -->
        <property name="connection.driver_class">com.mysql.jdbc.driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/test?characterencoding=utf-8</property>
        <property name="connection.username">root</property>
        <property name="connection.password">123456</property>
        <!-- sql dialect -->
        <property name="dialect">org.hibernate.dialect.mysqldialect</property>
        <property name="current_session_context_class">thread</property>
        <property name="show_sql">true</property>
        <property name="hbm2ddl.auto">update</property>


        <mapping resource="com/h/pojo/product.hbm.xml" />
        <mapping resource="com/h/pojo/category.hbm.xml"/>

    </session-factory>
</hibernate-configuration>

public class test1 {
    public static void main(string[] args) {

        sessionfactory factory=new configuration().configure().buildsessionfactory();
        session session = factory.opensession();
        session.begintransaction();


        category c =new category();
        c.setname("c1");
        session.save(c);

        product p = (product) session.get(product.class, 2);
        p.setcategory(c);
        session.update(p);

        session.gettransaction().commit();
        session.close();
        factory.close();
    }
}