小弟初学HIBERNATE请教一个小小的问题

package hibernate;

import org.hibernate.HibernateException;
import org.hibernate.cfg.Configuration;
import org.hibernate.SessionFactory;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.hibernate.Session;
import org.hibernate.Query;
import org.hibernate.Hibernate;
import org.hibernate.type.LongType;
import org.hibernate.Transaction;
import org.hibernate.ScrollableResults;

import java.util.*;
import java.lang.String;
import hibernate.Hello_Bean;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.*;
public class DeleteH extends Action{
private static SessionFactory factory=null;
public DeleteH()
{

}
public ActionForward execute(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)throws Exception
{
String ID=request.getParameter("id");

Configuration cfg = new Configuration().configure();//.buildSessionFactory();

if(factory==null)
{
factory = cfg.buildSessionFactory();
}
Session session = factory.openSession();

session.beginTransaction();
session.delete("from "+Hello_Bean.class.getName()+" where id="+ID);
session.getTransaction().commit();
//System.out.println(a);
session.flush();
session.close();
factory.close();
return (mapping.findForward("success"));
}

}
这个报错！
－--------------------------------------
HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Unknown entity: java.lang.String
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:545)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:486)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


root cause

org.hibernate.MappingException: Unknown entity: java.lang.String
org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:547)
org.hibernate.impl.SessionImpl.getEntityPersister(SessionImpl.java:1331)
org.hibernate.event.def.DefaultDeleteEventListener.onDelete(DefaultDeleteEventListener.java:59)
org.hibernate.impl.SessionImpl.fireDelete(SessionImpl.java:768)
org.hibernate.impl.SessionImpl.delete(SessionImpl.java:746)
hibernate.DeleteH.execute(DeleteH.java:44)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.


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Apache Tomcat/5.0.28
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DeleteH.java:44为：session.delete("from "+Hello_Bean.class.getName()+" where id="+ID);

String ID=request.getParameter("id");

id 不是string吧

改成

int ID= Integer.parseInt(request.getParameter("id").trim());

还是不行呀楼上的老大
还是说那句不对！session.delete("from "+Hello_Bean.class.getName()+" where id="+ID+"");

改下POJO的映射hbm.xml文件中 ID 的属性

例如：<id name="id" type="java.lang.Integer">