struts中出现的问题

config中的配置<action path="/admin/orderAction"
  type="com.shopping.action.orderAction"
  scope="session"
  name="orderForm">
  <forward name = "display" path= "/admin/centerOrder.jsp"/>
  <forward name = "searchorder" path= "/admin/searchorder.jsp"/>
  <forward name="orderselectone" path="/admin/order_oneresult.jsp"/>
 
  </action>Action中的调用
************************查询订单
 * @throws SQLException ****************************/
public  ActionForward orderselect(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) throws SQLException {
orderDao dao=new orderDao();
request.setAttribute("orderform", dao.selectone(request.getParameter("number")));
return mapping.findForward("orderselectone");
        }
  
dao中的方法
/**************************************查询
 * @throws SQLException ******************************/

public orderForm  selectone(String number) throws SQLException {

orderForm orderform = new orderForm();
Connection conn = null;
PreparedStatement pstmt = null; 
try{
String sql="select * from tb_order where id='"+number+"'";
pstmt.setString(1, number);
ResultSet rs=pstmt.executeQuery();

while(rs.next()){
orderform=new orderForm();
orderform.setId(Integer.valueOf(rs.getString("id")));
orderform.setMemberid(Integer.valueOf(rs.getString("memberid")));
orderform.setAdress(rs.getString("adress"));
orderform.setSetmoney(rs.getString("setmoney"));
orderform.setState(Integer.valueOf("state"));
orderform.setTel(rs.getString("tel"));
orderform.setNumber(rs.getString("number"));


}
}catch(SQLException e){

}
               return orderform;

}HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: java.lang.NullPointerException
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:535)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:433)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.shopping.core.Encoding.doFilter(Encoding.java:26)
root cause java.lang.NullPointerException
com.shopping.dao.orderDao.selectone(orderDao.java:63)
com.shopping.action.orderAction.orderselect(orderAction.java:106)
com.shopping.action.orderAction.execute(orderAction.java:43)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.shopping.core.Encoding.doFilter(Encoding.java:26)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.