正在做毕业设计，碰到一个问题，那位高手给看看是什么问题！
是一个Action!
错误提示:
HTTP   Status   500   -  

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type   Exception   report

message  

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

exception  

javax.servlet.ServletException:   could   not   load   an   entity:   [com.studorm.dao.Students#4]
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.exception.GenericJDBCException:   could   not   load   an   entity:   [com.studorm.dao.Students#4]
org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:91)
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:79)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
org.hibernate.loader.Loader.loadEntity(Loader.java:1799)
org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:93)
org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:81)
org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:2730)
org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:365)
org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:346)
org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:123)
org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:177)
org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:87)
org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:891)
org.hibernate.impl.SessionImpl.get(SessionImpl.java:828)
org.hibernate.impl.SessionImpl.get(SessionImpl.java:821)
com.studorm.struts.action.DeletestudentAction.execute(DeletestudentAction.java:54)
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

程序源码：
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