大神帮忙！！！用javabean传值的时候总是null
在以前建立的项目上可以传值，后来就传不了了。代码应该没问题吧，大神们帮帮忙。
package zx;
public class beanTest
{
private String username;
public beanTest()
{
}
public void setUsername(String username)
{
this.username = username;
}
public String getUsername()
{
return username;
}
}
<html>
<head>
<title>beanTest.html</title>
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<!--<link rel="stylesheet" type="text/css" href="./styles.css">-->
</head>
<body>
<form name="form1" action="beanTest.jsp" method="post">
<table>
<tr>
<td><input type="text" name="username"/></td>
</tr>
<tr>
<td><input type="submit" value="提交"/></td>
</tr>
</table>
</form>
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%
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>My JSP 'beanTest.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<jsp:useBean id="user" scope="page" class="zx.beanTest"/>
<%=user.getUsername() %>
</body>
</html>
