Java开发网 - 帮我诊断一下？

Topic: 帮我诊断一下？

1.帮我诊断一下？

Posted by: ququ_0811
Posted on: 2005-05-13 20:54

<html>
<head>
<title>ququ留言板</title>
</head>
<body bgcolor="#ccccff" vlink="#000000" alink="#666666">
<div align="center">
<p><font size="7">
<b><font size="+6">蛐蛐驿站 </font></b>
</font></p>
<form method="post" action="index.jsp">
<table width="75%" align="center" border=1>
<tr>
<td width="30%">
<div align="right">姓名 :</div>
</td>
<td width="70%">
<input type="text" name="name">
</td>
<tr>
</tr>
<td width="30%">
<div align="right">电子邮件 :</div>
</td>
<td width="70%">
<input type="text" name="email">
</td>
</tr>
<tr>
<td width="30%">
<div align="right">个人主页地字 :</div>
</td>
<td width="70%">
<input type="text" name="url" value="http://">
</td>
</tr>
<tr>
<td width="30%">
<p>请你留言</p>
</tr>
<td width="70%">
<textarea name="body" rows="5" cols="30"></textarea>
</td>
</tr>
<tr>
<td width="30%"> </td>
<td width="70%"> </td>
</tr>
<tr>
<td width="30%"> </td>
<td width="70%">
<table width="75">
</tr>
<td>
<input type="submit" name="send" value="提交">
</td>
<td>
<input type="reset" name="reset" value="重置">
</td>
</tr>
</table>
</td>
</tr>
</table>
</form>
<hr>
</div>
</body>
</html>

<html>
<head>
</head>
<body>
<%@ page language="java"import="java.sql.*,ququ.sql" %>
<%@ page contentType="text/html;charset=gb2312" %>
<jsp:useBean id="sqlbean" class="ququ.sql" scope="session"/>
<%! String name,email,url,body,sql; %>
<%
name=request.getParameter("name");
email=request.getParameter("email");
url=request.getParameter("url");
body=request.getParameter("body");
if(name!=""&&email!=""&&body!="")
{
sql="insert into guestbook(name,email,url,body)values('"+name+"','"+email+"','"+url+"','"+body+"')";
sqlbean.executeInsert(sql);
}
else
{
out.print("<b><font color=red >sorry ,please enter your name ,url ,email.and body!!!</font></b>");
}

%>
<%
ResultSet RScount = sqlbean.executeQuery("SELECT * FROM guestbook");
int i=0;
while(RScount.next())
{
i++;
}
%>
<%-- <p> --%>
<p><b>现在?%=i %> 条纪录</b></p>
<%
RScount.close();
i=0;
%>
<p> </p>
<%
ResultSet RS=sqlbean.executeQuery("SELECT * FROM guestbook");
while(RS.next())
{
name=RS.getString("name");
email=RS.getString("email");
url=RS.getString("url");
body=RS.getString("body");
%>
<table border=1 width=80%>
<tr>
<td width=30%>昵称：</td><td width=70% ><%=name%>
</tr>
<tr>
<td width=30%>电子邮件：</td><td width=70% ><a herf="mailto:<%=email%>"><%=email%></a></td>
</tr>
<tr>
<td width=30%>个人主页：</td><td width=70% ><a herf="<%=url%>"><%=url%></a></td>
</tr>
<tr>
<td width=30%>内容：</td><td width=70% ><%=body%></td>
</tr>
</table>
<hr>
<%
}
RS.close();

%>
</body>
</html>
package ququ;
import java.sql.*;
public class sql
{

  String sDBDriver="sun.jdbc.odbc.JdbcOdbcDriver";
  String sConnStr="jdbc:odbc:mydata";
  Connection conn=null;
  ResultSet rs=null;
  public sql()
  {
  try
   {
    Class.forName(sDBDriver);

   }catch(java.lang.ClassNotFoundException e)
   {
     System.err.println("sql():"+e.getMessage());
   }catch(java.lang.NullPointerException e)
   {
     System.err.println("sql():"+e.getMessage());
     }

   }


public void executeInsert(String sql)
{
  try
  {
    conn=DriverManager.getConnection(sConnStr);
    Statement stmt=conn.createStatement();
    stmt.executeUpdate(sql);


  }catch(SQLException ex)
  {
    System.err.println("sql.executeUpdata:"+ex.getMessage());

  }
}
public ResultSet executeQuery(String sql)
{
   rs=null;
   try
   {
    conn=DriverManager.getConnection(sConnStr);
    Statement stmt=conn.createStatement();
    rs=stmt.executeQuery(sql);


   }catch(SQLException ex)
   {
    System.err.println("sql.executeUpdata:"+ex.getMessage());

   }
return rs;
}
public void executeDelete(String sql)
{
   try
   {
    conn=DriverManager.getConnection(sConnStr);
    Statement stmt=conn.createStatement();
    stmt.executeUpdate(sql);


  }catch(SQLException ex)
   {
    System.err.println("sql.executeUpdata:"+ex.getMessage());

   }
   }
}
运行结果
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:373)
  org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
  org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.NullPointerException
  org.apache.jsp.index_jsp._jspService(org.apache.jsp.index_jsp:85)
  org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:99)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
  org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:325)
  org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
  org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.7 logs.

--------------------------------------------------------------------------------

Apache Tomcat/5.5.7
大哥们，小弟初学请指教。