hibernate中HQL如何调用自定义函数

CREATE OR REPLACE FUNCTION WX_F_GET_PARTYSTR(V_DEPT_ID NUMBER --人员信息中包含的部门ID) RETURN VARCHAR2 AS
      T_UP_DEPT NUMBER(10);--上级部门ID，临时参数
      T_DEPT_TEMP VARCHAR2(2000);--部门名称
      T_DEPT_STR VARCHAR2(2000);--要返回的已拼接部门名称字符串
      BEGIN
          //省略
     END WX_F_GET_PARTYSTR;

import org.hibernate.dialect.Oracle10gDialect;
import org.hibernate.dialect.function.SQLFunctionTemplate;
import org.hibernate.type.StringType;
public class MyDialect extends Oracle10gDialect{
	public MyDialect(){
		super();
		//函数名必须是小写，试验大写出错
		//SQLFunctionTemplate函数第一个参数是函数的输出类型，varchar2对应new StringType()    number对应new IntegerType()
		//?1代表第一个参数,?2代表第二个参数     这是数据库wx_f_get_partystr函数只需要一个参数，所以写成wx_f_get_partystr(?1)
		this.registerFunction("wx_f_get_partystr", new SQLFunctionTemplate(new StringType(), "wx_f_get_partystr(?1)"));
	}
}

<property name="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</property>

<property name="hibernate.dialect">com.wx.web.struts.MyDialect</property>

String hql="select new com.entity.wx.AddressBook(a.userId,a.userName," +
    " wx_f_get_partystr(a.department), " +
    "a.position, a.mobile,a.email,a.weixinId,a.avatar,a.status) " +
    "from WxContacts a where a.userId in("+userId_str+") order by substr(a.userName,0,1)";