hibernate删除的问题，急

我想根据t_user这张表里的vc_id做批量删除，初学，请多指教
删除的代码如下：
public void delete(String ids){
try {
String strSql = "from TUser as t where t.vcId in ("+ids+")";
Session session = getHibernateTemplate().getSessionFactory().openSession();
Transaction ts = session.beginTransaction();
System.out.println("AAAAAAAAAAAAA");
session.delete(strSql);
ts.commit();
session.close();
} catch (RuntimeException re) {
log.error("delete failed", re);
throw re;
}
}报错如下：
delUser_err==org.hibernate.MappingException: Unknown entity: java.lang.String
2009-10-16 17:59:19 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at org.apache.struts.util.RequestUtils.actionIdURL(RequestUtils.java:1011)
at org.apache.struts.util.RequestUtils.actionIdURL(RequestUtils.java:996)
at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:371)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:232)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.bs.hyg.util.EncodingFilter.doFilter(EncodingFilter.java:20)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:857)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:565)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1509)
at java.lang.Thread.run(Unknown Source)