大家帮忙看看这段出什么毛病了

Question

出现问题如下：
org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:358)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
root cause java.lang.NullPointerException
org.apache.jsp.index2_jsp._jspService(index2_jsp.java:81)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

Answer 1

ResultSet rs=stmt.executeQuery("select * from guestbook order by serial_no disc");
中stmt为null，没有初始化

Answer 2

看看这个里面的表字段跟数据库里是否一致：
<td width="10%" align="center"><%=rs.getString("name")%>
<td width="20%" align="center"><%=rs.getString("emote")%>
<td width="15%" align="center"><%=rs.getString("guest_time")%>
<td width="55%" align="center"><%=rs.getString("content")%>

Answer 3

空指针错误哦。
public void firm(String name,String emote,String content)
{
   try
  {
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
    conn=DriverManager.getConnection("jdbc:odbc:firm");
    stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
   }
    catch(Exception ex)
    {
      System.err.print(ex.toString());
      }
    }
你这个函数写再那里，也没有调用呀，那stmt肯定是空的喽

Answer 4

<%@page contentType="text/html;charser=gb2312"%>
charser??
改成:
charset

Answer 5

在ResultSet rs=stmt.executeQuery("select * from guestbook order by serial_no disc");的前面加上firm（"","",""）；看看