java.lang.NullPointerException异常
<%@ page language="java" pageEncoding="GBK" %>
<%@ include file="../../common.jsp" %>
<LINK href=../../css/css.css rel=stylesheet>
<style type="text/css">
<!--
.STYLE1 {font-family: Verdana, Arial, Helvetica, sans-serif}
-->
</style>
<link href="../css/css.css" rel="stylesheet" type="text/css">
<body bgcolor="#F4F2F2" topmargin="4">
<br/>
<% Database dsm=new Database();
ResultSet rs=null;
int N_id=0;
String USER_name="";
String sqlStr="";
String N_sign="";
String N_addDate="";
String N_addUser="";
String N_title="";
String N_content="";
String N_sort="";
String S_id="";
String P_id="";
%>
<%
N_id=3;
System.out.println(N_id);
USER_name=(String)session.getAttribute("USER_name");
sqlStr="select * from newsshow where N_id=3";
//System.out.println(sqlStr);
try{
dsm.setSqlStr(sqlStr);
dsm.executeQuery();
rs=dsm.getRs();
while(rs.next()){
N_title=rs.getString("N_title");
N_content=rs.getString("N_content");
N_addDate=(rs.getString("N_addDate")).substring(0,19);
N_addUser=rs.getString("N_addUser");
N_sort=rs.getString("S_name");
N_sign=rs.getString("P_name");
%>
<form method="POST" name="myform" action="../../servlet/SortAdd">
<table width="700" height="127" border="0" align="center"
cellpadding="0" cellspacing="1" bgcolor="#BBB3AA">
<tr bgcolor="FBF5F0">
<td height="30" colspan="4" align="center"><font color="#CC0000"><b>新闻类别信息修改
</b></font></td>
</tr>
<tr bgcolor="#FFFFFF">
<td width="89" height="25" align="center">
<font face="Verdana, Arial, Helvetica, sans-serif">
新闻标题:</font> </td>
<td colspan="3">
<input name="title" type="text" id="title" size="55" value="<%=N_title %>"></td>
</tr>
<tr bgcolor="#FFFFFF">
<td height="25" align="center">新闻类型:</td>
<td width="234" height="20" align="left" >
<input name="N_sort" type="text" id="N_sort" value="<%=N_sort %>" size="20">
<input type="button" name="editsort" value="更改" onClick="window.location='sortselect2.jsp'"></td>
<td width="97" align="center">添加时间:</td>
<td width="275" align="left"> <%=N_addDate %></td>
</tr>
<tr bgcolor="#FFFFFF">
<td height="25" align="center">针对省份:</td>
<td height="20" align="left">
<%
P_id=(null==request.getParameter("P_id")?"00":request.getParameter("P_id"));
System.out.println(P_id);
if(!P_id.equals("00")){
ResultSet rs3=null;
String sql3="select * from tb_pro where P_id='"+P_id+"'";
try{
dsm.setSqlStr(sql3);
dsm.executeQuery();
System.out.println(sql3);
rs3=dsm.getRs();
while(rs3.next()){
N_sign=rs.getString("P_name");
System.out.println("=="+N_sign);
session.setAttribute("P_id",P_id);
}
System.out.println(N_sign);
}
catch(Exception ee){}
}
%>
<input name="N_sign" type="text" id="N_sign" value="<%=N_sign %>" size="20">
<input type="button" name="editpro" value="更改" onClick="window.location='proselect.jsp'"></td>
<td width="97" height="20" align="center">添加作者:</td>
<td height="20" align="left"> <%=N_addUser %></td>
</tr>
<tr bgcolor="#FFFFFF">
<td height="20" align="center">新闻内容:</td>
<td height="20" colspan="3" align="left"> <input type="hidden" name="content" value="<%=N_content %>"><iframe src='../../eWebEditor/ewebeditor.htm?id=content' frameborder=0 scrolling=no width='550' HEIGHT='350'></iframe></td>
</tr>
<tr bgcolor="#FFFFFF">
<td height="30" colspan="4" align="right"><span class="STYLE1">
<input type="submit" name="Submit2" value="添加">
<input type="reset" name="Submit" value="重置">
<input type="button" name="Submit3" value="返回" onClick="javascript:history.go(-1);">
</span></td>
</tr>
</table>
<%}}catch(Exception ew){System.out.println(ew.toString());} %>
</form>
上面是我的JSP页面代码
00
3
4
select * from tb_pro where P_id='4'
java.lang.NullPointerException
这是在控制台输出的结果
在传一个值过来后,能接到,也能执行SQL查询,但是一到rs(N_sign=rs.getString("P_name");)那里就走不下去了
哪位高手知道错误原因啊,帮帮忙!谢谢了!