善良的各位?????????这是哪门子问题????????小虾米在这谢过了
各位prawn:         JSP页面调试出现难题:   
 HTTP   Status   500   -      
 --------------------------------------------   
 type   Exception   report   
 message      
 description   The   server   encountered   an   internal   error   ()   that   prevented   it   from   fulfilling   this   request.   
 exception       
org.apache.jasper.JasperException  	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372) 
 	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292) 
 	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236) 
 	javax.servlet.http.HttpServlet.service(HttpServlet.java:802)     
 root   cause       
java.lang.NullPointerException  	org.apache.jsp.reg2_jsp._jspService(reg2_jsp.java:79) 
 	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94) 
 	javax.servlet.http.HttpServlet.service(HttpServlet.java:802) 
 	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324) 
 	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292) 
 	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236) 
 	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.   
 JSP原文如下:----------------------------------   
  <%@   page   contentType= "text/html;   charset=gb2312 "   language= "java "   import= "java.sql.* "   
errorPage= " "   %>  
  <!DOCTYPE   HTML   PUBLIC    "-//W3C//DTD   HTML   4.01   Transitional//EN "    "http://www.w3.org/TR/html4/loose.dtd ">  
  <script   language= "javascript ">  
 function   backward() 
 { 
 	history.back(); 
 } 
  </script>    
  <html>  
  <head>  
  <meta   http-equiv= "Content-Type "   content= "text/html;   charset=gb2312 ">  
  <title> please   check   the   following   form </title>  
  </head>  
  <style   type= "text/css ">  
  <!--@import   url(css/jsp.css);-->  
  </style>    
  <body   bgcolor= "#FFFFFF "   text= "#006699 ">  
  <%@   page   language= "java "   import= "java.sql.* "%>  
  <jsp:useBean   id= "db "   scope= "page "   class= "opendb.opendb "/>  
  <% 
 String   uid=request.getParameter( "uid "); 
 String   sql= "select   *   from   custom   where   uid= ' "+uid+ " ' "; 
 ResultSet   rs   =   db.executeQuery(sql); 
 if(rs.next()) 
 { 
                      rs.close();   
 %>  
  <p> sorry!   the   ID   your   selected   has   been   regestered   ,please   choose   another &nb