作登录出了问题,非常郁闷！！

出现以下问题：
HTTP Status 404 - /LoginProject/com/login/LoginServlet--------------------------------------------------------------------------------type Status reportmessage /LoginProject/com/login/LoginServletdescription The requested resource (/LoginProject/com/login/LoginServlet) is not available.
--------------------------------------------------------------------------------
login.jsp<%@page contentType="text/html"%>
<%@page pageEncoding="GBK"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd"><html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=GBK">
    <title>登录</title>
    <script language="JavaScript">
            <!--
            function validateLogin(){
                 var strUserName=document.frmLogin.txtUserName.value;
                 var strPassword=document.frmLogin.txtPassword.value;
                 if(strUserName==""){
                      alert("请输入用户名！");
                      return false;
                  }
                  if(strPassword == ""){
                      alert("请输入密码！");
                      return false;
                  }
            }
            -->
    </script>
</head>
<body>
<form name="frmLogin" action="LoginServlet" method="post" onsubmit="javaScript: return validateLogin();">
<table  align="center" border="0" width="273" bgcolor="#FFcccc">
    <tr>
        <td align="right" height="47" valign="bottom" width="94">用户名：</td>
        <td height="47" valign="bottom" width="172"><input name="txtUserName" type="text"></td>
    </tr>
    <tr>
        <td align="right" height="47" valign="bottom" width="94">密&nbsp;&nbsp;码：</td>
        <td height="47" valign="bottom" width="172"><input name="txtPassword" type="password"></td>
    </tr>
    <tr>
        <td align="right" height="44" width="94"></td>
        <td height="44" width="172"><input name="submit" type="submit" value="提交">&nbsp;&nbsp;&nbsp;<input name="reset" type="reset" value="重置"></td>
    </tr>
    <tr>
        <td></td>
        <td></td>
    </tr>
    </tbody>
</table></form>
</body>
</html>LoginServlet.class
/*
 * LoginServlet.java
 *
 * Created on 2007年4月2日, 下午8:54
 */package com.login;import java.io.*;
import java.net.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.tagext.TryCatchFinally;
import javax.xml.soap.SAAJMetaFactory;/**
 *
 * @author Administrator
 * @version
 */
public class LoginServlet extends HttpServlet
{
    
    
    public LoginServlet()
    {
        super();
    }
    
    
    protected void doGet(HttpServletRequest request, HttpServletResponse response, String sa)
    throws ServletException, IOException
    {
        
    }
    
    /** Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response, String sa)
    throws ServletException, IOException
    {
       response.setContentType("text/html");
        String result="";
        String strUserName=request.getParameter("txtUserName");
        String strPassword=request.getParameter("txtPassword");
        if((strUserName==null)||(strUserName.equals(""))||(strUserName.length()>20))
        {
            result="请输入用户名（不超过20字符）";
            request.setAttribute("error_username",result);
            response.sendRedirect("login.jsp");
        }
        if((strPassword==null)||(strPassword.equals(""))||(strPassword.length()>20))
        {
            result="请输入密码（不超过20字符）";
            request.setAttribute("error_username",result);
            response.sendRedirect("login.jsp");
        }
        Connection con=null;
        Statement stmt=null;
        ResultSet rs=null;
        try
        {
            Class.forName("net.sourceforge.jtds.jdbc.Driver");
        } catch (ClassNotFoundException ex)
        {
            ex.printStackTrace();
        }
        String url="jdbc:jtds:sqlserver://localhost:1433;DatabaseName=jspstudy";
        try
        {
            con=DriverManager.getConnection(url,sa,"");
        }
        catch (SQLException ex)
        {
            ex.printStackTrace();
        }
        try
        {
            String sql="select * from userinfo where username='"+strUserName+"'and userPwd='"+strPassword+"'";
            stmt=con.createStatement();
            rs=stmt.executeQuery(sql);
            if(rs.next())
            {
                request.getSession(true).setAttribute("username",strUserName);
                response.sendRedirect("login_success.jsp");
            }
            else
            {
                response.sendRedirect("login_failure.jsp");
            }
        }
        catch(SQLException sqlExc)
        {
            sqlExc.printStackTrace();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        finally
        {
            try
            {
                if(rs!=null)
                {
                    rs.close();
                }
            }
            catch(SQLException sqlExc)
            {
                sqlExc.printStackTrace();
            }
        }
    }
    
}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>com.login.LoginServlet</servlet-class>
        <load-on-startup>2</load-on-startup>
     </servlet>
     <servlet-mapping>
         <servlet-name>LoginServlet</servlet-name>
         <url-pattern>/LoginServlet</url-pattern>
     </servlet-mapping>
         <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>Login.jsp</welcome-file>
    </welcome-file-list>
    </web-app>
这上面市我主要的代码，我现是在做第一个jsp 程序，这是比较，很基础的 ，都做不出来，我好郁闷！！！