user is not mapped [from user] 报错解决方法

Hibernate配置：

<hibernate-mapping>
    <class name="com.um.user.User" table="user">
         <id name="id" type="java.lang.Integer">
            <column name="ID" precision="22" scale="0" />
            <generator class="identity" />
        </id>
        <property name="username" type="java.lang.String">
            <column name="USERNAME" length="100" not-null="false">
                <comment>用户名</comment>
            </column>
        </property>
        <property name="password" type="java.lang.String">
            <column name="PASSWORD" length="100" not-null="false">
                <comment>密码</comment>
            </column>
        </property>
        
    </class>

</hibernate-mapping>

查询数据库：
public List<User> findAll(){
        String queryString = "from user";
        List<User> list =this.getHibernateTemplate().find(queryString);
        return list;