大家帮帮我啊，不会忘记你们大恩大德的，顶也有分，而且还可以加分。

运行一个注册摸块出错，只贴出了相关的代码（一个JSP，一个JAVABEAN）。

JSP代码如下
<%@ page contentType="text/html;charset=gb2312" pageEncoding="gb2312" %>
<html>
<head>
<title>Shopping123</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<link href="styles/shoppingstyle.css" rel="stylesheet" type="text/css">
</head>
<body bgcolor="#FFFFFF" leftmargin="0" topmargin="0">
<jsp:useBean id="checklogin" scope="page" class="abc.checkLogin" />
<%
boolean login = checklogin.check(request,response);
%>
<table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
<tr bgcolor="#990000">
<td height="80" colspan="5"><table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="120"> </td>
<td class="caption">Shopping123</td>
<td width="200"> </td>
</tr>
</table></td>
</tr>
<tr>
<td width="200" align="center" valign="top"><table width="100%" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td> </td>
</tr>
</table>
<%
if(!login){
%>
<table width="90%" border="0" align="center" cellpadding="0" cellspacing="1" bgcolor="#CCCCCC">
<form name="form1" method="post" action="/servlet/login">
<tr align="center" bgcolor="#CCCCCC">
<td height="30" colspan="2" class="deepred">卖场入口</td>
</tr>
<tr>
<td width="50%" height="24" align="center" bgcolor="#FFFFFF">会员</td>
<td align="center" bgcolor="#FFFFFF"><input name="username" type="text" id="username" size="10"></td>
</tr>
<tr>
<td height="24" align="center" bgcolor="#FFFFFF">密码</td>
<td align="center" bgcolor="#FFFFFF"><input name="password" type="text" id="password" size="10"></td>
</tr>
<tr>
<td height="24" align="center" bgcolor="#FFFFFF"><a href="reg.jsp" target="_blank" class="red">注册</a></td>
<td align="center" bgcolor="#FFFFFF"><input type="submit" name="Submit" value="进入"></td>
</tr>
</form>
</table>
<%
}
else
{
out.println("您好，" + checklogin.getUserName() + "!");
}
%>
</td>
<td width="1" valign="top" bgcolor="#CCCCCC"></td>
<td width="400"> </td>
<td width="1" valign="top" bgcolor="#CCCCCC"></td>
<td width="200"> </td>
</tr>
<tr align="center" bgcolor="#990000">
<td height="60" colspan="5" class="white">copyright© 2003 Shopping123</td>
</tr>
</table>
</body>
</html>

JAVABEAN如下：
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

//class checkLogin
public class checkLogin
{
public String username = "";

public boolean check(HttpServletRequest req,HttpServletResponse res)
throws IOException,ServletException
{
String cookieName = "username";
Cookie[] myCookies = req.getCookies();
this.username = this.getCookieValue(myCookies,cookieName,"not found");
PrintWriter out = res.getWriter();
if(this.username != null)
{
//out.println("早上好，" + this.username + "！");
return true;
}else{
out.println("登陆失败！");
return false;
}

}

public String getUserName()
{
return this.username;
}

public static String getCookieValue(Cookie[] cookies,String cookieName,String defaultValue)
{
for(int i=0;i<cookies.length;i++) {
Cookie cookie = cookies[i];
if (cookieName.equals(cookie.getName()))
return(cookie.getValue());
}
return(defaultValue);
}
}