<%@ page language="java" pageEncoding="gb2312"%>
<jsp:directive.page import="java.sql.ResultSet"/>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>查询手机</title>
</head>
<jsp:useBean id="JDBConnection" class="database.JDBConnection"/>
<body>
<%
String price=request.getParameter("price");
String sql=null;
if(price.equals("1000"))
{
sql="select * from mobile where 手机价格 <1000";
}
if(price.equals("2000"))
{
sql="select * from mobile where 手机价格 between 1000 and 2000";
}
if(price.equals("3000"))
{
sql="select * from mobile where 手机价格 between 2000 and 3000";
}
if(price.equals("4000"))
{
sql="select * from mobile where 手机价格 >3000";
}
ResultSet rs=null;
int pagesize=5;
int rowcount=0;
int pagecount=1;
int showpage=1;
rs=JDBConnection.executeQuery(sql);
rs.last();
rowcount=rs.getRow();
out.println("数据库的手机总共有"+rowcount+"部,相关信息如下");
showpage=1;
pagecount=((rowcount%pagesize)==0?(rowcount/pagesize):(rowcount/pagesize)+1);
String topage=request.getParameter("topage");
if(topage!=null)
{
showpage=Integer.parseInt(topage);
if(showpage>pagecount)
{
showpage=pagecount;
}
else if(showpage<=0)
{
showpage=1;
}
}
rs.absolute((showpage-1)*pagesize+1);
for(int i=1;i<=pagesize;i++)
{
%>
<table width="685" height="114" align="center" bordercolor="#CCCCFF" >
<tr>
<td width="106" rowspan="3" bgcolor="#FFFFFF"><img src="<%= rs.getString("picture")%>"><a href="cart_insert.jsp?a=<%=rs.getString("手机价格")%>&&b=<%=rs.getString("手机型号")%>&&c=<%=rs.getString("手机种类")%>"><img src="picture/web/cart_new.gif" width="120" height="23" border=0 align="bottom"></a></td>
<td width="232" height="20" bgcolor="#CCCCFF"><%= rs.getString("手机种类")%><%= rs.getString("手机型号")%></td>
<td width="156" bgcolor="#CCCCFF"><div align="center">手机价格</div></td>
<td width="173" bgcolor="#CCCCFF"><%= rs.getInt("手机价格")%>元</td> </tr>
<tr>
<td height="59" colspan="3"><%= rs.getString("手机信息")%></td>
</tr>
<tr>
<td height="25" colspan="3" bgcolor="#CCCCFF"><center>手机具体信息</center></td>
</tr>
<%
if(!rs.next())
break;
}
%> </table>
<table align="center">
<tr>
<td>共<%= pagecount%>页</td>
<td><%= pagesize%>条/页</td>
<td><a href="mobile_price_select.jsp?topage=<%=1%>">第一页</a></td>
<td><a href="mobile_price_select.jsp?topage=<%=showpage-1%>">上一页</a></td>
<td><a href="mobile_price_select.jsp?topage=<%=showpage+1%>">下一页</a></td>
<td><a href="mobile_price_select.jsp?topage=<%=pagecount%>">最后一页</a></td>
<td>当前第<input name="topage" type="text" size="1" value="<%=showpage%>" disabled="disabled"/>页</td>
</tr>
</table>
</body>
</html>
[align=center]
点击下一页就出错[/align]
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Exception in JSP: /mobile_price_select.jsp:2118: <%
19: String price=request.getParameter("price");
20: String sql=null;
21: if(price.equals("1000"))
22: {
23: sql="select * from mobile where 手机价格 <1000";
24: }
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:504)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause
java.lang.NullPointerException
org.apache.jsp.mobile_005fprice_005fselect_jsp._jspService(mobile_005fprice_005fselect_jsp.java:76)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.17 logs.
<jsp:directive.page import="java.sql.ResultSet"/>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>查询手机</title>
</head>
<jsp:useBean id="JDBConnection" class="database.JDBConnection"/>
<body>
<%
String price=request.getParameter("price");
String sql=null;
if(price.equals("1000"))
{
sql="select * from mobile where 手机价格 <1000";
}
if(price.equals("2000"))
{
sql="select * from mobile where 手机价格 between 1000 and 2000";
}
if(price.equals("3000"))
{
sql="select * from mobile where 手机价格 between 2000 and 3000";
}
if(price.equals("4000"))
{
sql="select * from mobile where 手机价格 >3000";
}
ResultSet rs=null;
int pagesize=5;
int rowcount=0;
int pagecount=1;
int showpage=1;
rs=JDBConnection.executeQuery(sql);
rs.last();
rowcount=rs.getRow();
out.println("数据库的手机总共有"+rowcount+"部,相关信息如下");
showpage=1;
pagecount=((rowcount%pagesize)==0?(rowcount/pagesize):(rowcount/pagesize)+1);
String topage=request.getParameter("topage");
if(topage!=null)
{
showpage=Integer.parseInt(topage);
if(showpage>pagecount)
{
showpage=pagecount;
}
else if(showpage<=0)
{
showpage=1;
}
}
rs.absolute((showpage-1)*pagesize+1);
for(int i=1;i<=pagesize;i++)
{
%>
<table width="685" height="114" align="center" bordercolor="#CCCCFF" >
<tr>
<td width="106" rowspan="3" bgcolor="#FFFFFF"><img src="<%= rs.getString("picture")%>"><a href="cart_insert.jsp?a=<%=rs.getString("手机价格")%>&&b=<%=rs.getString("手机型号")%>&&c=<%=rs.getString("手机种类")%>"><img src="picture/web/cart_new.gif" width="120" height="23" border=0 align="bottom"></a></td>
<td width="232" height="20" bgcolor="#CCCCFF"><%= rs.getString("手机种类")%><%= rs.getString("手机型号")%></td>
<td width="156" bgcolor="#CCCCFF"><div align="center">手机价格</div></td>
<td width="173" bgcolor="#CCCCFF"><%= rs.getInt("手机价格")%>元</td> </tr>
<tr>
<td height="59" colspan="3"><%= rs.getString("手机信息")%></td>
</tr>
<tr>
<td height="25" colspan="3" bgcolor="#CCCCFF"><center>手机具体信息</center></td>
</tr>
<%
if(!rs.next())
break;
}
%> </table>
<table align="center">
<tr>
<td>共<%= pagecount%>页</td>
<td><%= pagesize%>条/页</td>
<td><a href="mobile_price_select.jsp?topage=<%=1%>">第一页</a></td>
<td><a href="mobile_price_select.jsp?topage=<%=showpage-1%>">上一页</a></td>
<td><a href="mobile_price_select.jsp?topage=<%=showpage+1%>">下一页</a></td>
<td><a href="mobile_price_select.jsp?topage=<%=pagecount%>">最后一页</a></td>
<td>当前第<input name="topage" type="text" size="1" value="<%=showpage%>" disabled="disabled"/>页</td>
</tr>
</table>
</body>
</html>
[align=center]
点击下一页就出错[/align]
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Exception in JSP: /mobile_price_select.jsp:2118: <%
19: String price=request.getParameter("price");
20: String sql=null;
21: if(price.equals("1000"))
22: {
23: sql="select * from mobile where 手机价格 <1000";
24: }
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:504)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause
java.lang.NullPointerException
org.apache.jsp.mobile_005fprice_005fselect_jsp._jspService(mobile_005fprice_005fselect_jsp.java:76)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.17 logs.
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这里是你要发的请求?toppage
<%
19: String price=request.getParameter("price");
20: String sql=null;
21: if(price.equals("1000"))
22: {
23: sql="select * from mobile where 手机价格 <1000";
24: }
当你点击下一叶的时候并没有传递price参数。这个时候报NullPointerException
解决办法:
把你的业务逻辑分开!
1:接受客户的手机价格,显示出结果集
2:在结果集上实现分页。
你就需要去判断用户到底是在请求数据还是在请求分页。分开做就OK了
那句改成if("1000".equals(price)) )