Hibernate_过滤器

过滤器的定义:

<hibernate-mapping>
    <class name="com.sunflower.yuan.pojo.Family" table="family">
        <id name="id" column="id">
            <generator class="uuid"></generator>
        </id>

        <property name="username" column="username" type="string"></property>
        <property name="address" column="address" type="string"></property>
        <property name="cost" column="cost" type="double"></property>

        <!-- 声明使用过滤器，规定过滤器过滤内容 -->
        <filter name="costFilter" condition="cost>:inputCost"></filter>
    </class>

    <!-- 定义过滤器,带参数cost -->
    <filter-def name="costFilter">
        <filter-param name="inputCost" type="double" />
    </filter-def>
</hibernate-mapping>

过滤器的使用:

public class Test {
    public static void main(String[] args) {
        Session session = HibernateUtil.getSession();
        Transaction ts = null;

        try {
            ts = session.beginTransaction();

            Query query = session.createQuery("from Family");

            Filter filter = session.enableFilter("costFilter");
            filter.setParameter("inputCost", new Double(550));

            List<Family> list = query.list();
            for (Family family : list) {
                System.out.println("Username:" + family.getUsername()
                        + ", Cost:" + family.getCost());
            }

            ts.commit();
        }
        catch (Exception e) {
            if (ts != null && ts.isActive())
                ts.rollback();
            e.printStackTrace();
        }
        finally {
            HibernateUtil.closeSession(session);
        }
    }
}

第１１行是激活过滤器，第１２行是传递过滤器参数值。

执行后的SQL语句：

 select
        family0_.id as id0_,
        family0_.username as username0_,
        family0_.address as address0_,
        family0_.cost as cost0_ 
    from
        family family0_ 
    where
        family0_.cost>?

第９行的判断where字句是过滤器附加上去的。

 

Session接口中与Filter对象有关的方法：

方法名	解释
public Filter enableFilter(String filterName)	激活某个过滤器的使用
public Filter getEnableFilter(String filterName)	获取某个激活的过滤器
public void disableFilter(String filterName)	停止某个过滤器的使用