学生号在学生表里面是主键,类型是varchar,id生成器是assigned我在程序中想要修改这个学生号,却提示说:java.lang.NullPointerExceptionexception javax.servlet.ServletException: java.lang.NullPointerException
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:516)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:423)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:415)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
filter.Encoding.doFilter(Encoding.java:41)
root cause java.lang.NullPointerException
action.EditStuAction.execute(EditStuAction.java:38)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:415)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
filter.Encoding.doFilter(Encoding.java:41)
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:516)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:423)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:415)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
filter.Encoding.doFilter(Encoding.java:41)
root cause java.lang.NullPointerException
action.EditStuAction.execute(EditStuAction.java:38)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:415)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
filter.Encoding.doFilter(Encoding.java:41)
public class EditStuAction extends Action{
public ActionForward execute(ActionMapping mapping,ActionForm form,
HttpServletRequest request,HttpServletResponse response){
EditStuForm editStuForm=(EditStuForm)form;
String id=editStuForm.getId();
String name=editStuForm.getName();
String password=editStuForm.getPassword();
String jiguan=editStuForm.getJiguan();
String department=editStuForm.getDepartment();
String sex=editStuForm.getSex();
Integer =editStuForm.getMark();
String tel=editStuForm.getTel();
String phone=editStuForm.getPhone();
String email=editStuForm.getEmail();
ManStuDAO manStuDao=new ManStuDAO();
Student stu;
stu=manStuDao.getStuById(id);
stu.setId(id);
stu.setName(name);
stu.setPassword(password);
stu.setDepartment(department);
stu.setEmail(email);
stu.setJiguan(jiguan);
stu.setSex(sex);
stu.setTel(tel);
stu.setMark();
stu.setPhone(phone);
if(manStuDao.update(stu)){
if(request.getSession().getAttribute("self")=="1")
return mapping.findForward("stuEditSuccess");
else
return mapping.findForward("editSuccess");
}else
return mapping.findForward("error");
}}
stu.setId(id);stu不必setId 了吧