新手问题，一下午了。。。。

Question

JAVAbean 如下
package Main_Bean.Opera;public class Login
{
private String UserName;
private String Password;
public void setUserName(String U)
{
this.UserName = U;
} public void setPassword(String P)
{
this.Password = P;
} public String getUserName()
{
return this.UserName;
} public String getPassword()
{
return this.Password;
}
}
JSP 页面如下表单:
<form name="form" method="post" action="login.jsp">
                                  <table width="100%" border="0" align="right" cellpadding="0" cellspacing="0">
                                    <tr>
                                      <td width="37%" height="35"><div align="center">登陆名称：</div></td>
                                      <td width="63%"><div align="left">
                                          <input name="UserName" type="text" class="input1" id="UserName">
                                      </div></td>
                                    </tr>
                                    <tr>
                                      <td height="35"><div align="center">登陆密码：</div></td>
                                      <td><input name="Password" type="text" class="input1" id="Password"></td>
                                    </tr>
                                    <tr>
                                      <td height="38" colspan="2"><div align="center">
                                        <input name="imageField" type="image" src="images/LoginButton.jpg" width="100" height="21" border="0">
                                      </div></td>
                                    </tr>
                                    <tr bgcolor="#FFFFFF">
                                      <td height="98" colspan="2"><table width="182" border="0" align="center" cellpadding="0" cellspacing="0">
                                       <%//if (error.equals(new String("1"))){%>
      <tr>
                                            <td height="22"><div align="center" class="style6">用户名或密码错误!</div></td>
                                          </tr>
                                       <%
   //}
   %>
      <tr>
                                            <td width="182" height="22"><div align="left">
                                                <input type="checkbox" name="checkbox" value="checkbox">
                                                <FONT color=#666666><B><FONT face="Arial, Helvetica, sans-serif">安全浏览(页面自动过期)</FONT></B></FONT></div></td>
                                          </tr>
                                          <tr>
                                            <td height="22"><div align="left"><FONT color=#666666><B><FONT face="Arial, Helvetica, sans-serif">
                                                <INPUT id=Use_Cookie type=checkbox value=1 name=Use_Cookie>
                                        使用Cookie保存密码</FONT></B></FONT></div></td>
                                          </tr>
                                      </table></td>
                                    </tr>
                                  </table>
                              </form>
JSP<%@ page contentType="text/html; charset=gb2312"%>
<jsp:useBean id="cac" class="Main_Bean.Opera.Login" scope="page">
<jsp:setProperty name="cac" property="*"/>
</jsp:useBean><%
out.println("aa");
out.println(cac.getUserName());
out.println(cac.getPassword());
//String cc = cac.getUserName();
//out.println(cc);
//response.sendRedirect("main.jsp");
%>在Login.jsp中，JAVABEAN没有自动接受由表单传递近来的参数，
也就是说
out.println(cac.getUserName());
out.println(cac.getPassword());
为null null
我用的是TOMCAT 5.0 捆饶一下午了。
谁可以告诉我为什么?

Answer 1

表但中的name属性首字母要小写，另Bean中的属性也要改成小写
如：
private String userName;private String password;方法不要改