Servlet提交表单出现404错误

这是我的代码部分，感觉没有错误，我是初学者，请大家帮帮忙
我用的是NetBeans7.0login.html
<!DOCTYPE HTML PUBLIC "-//w3c//dtd html 4.0 transitional//en">
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312"> 
<title>提交表单数据</title> 
</head> 
<body bgcolor="#FFFFFF"> 
<h1 align="center"> <b>欢迎登录系统</b></h1> 
<form action="getpostdata" method ="post"> <p> </p> 
  <table width="52%" border="2" align="center">
    <tr bgcolor="#FFFFCC"> 
      <td align="center" width="43%"> <div align="center">用户名:</div></td>
      <td width="57%"> <div align="left"> 
          <input type="text" name="username">
        </div></td>
    </tr>
    <tr bgcolor="#CCFF99"> 
      <td align="center" width="43%"> <div align="center">密 码:</div></td>
      <td width="57%"> <div align="left"> 
          <input type="password" name="password">
        </div></td>
    </tr>
  </table> 
<p align="center"> 
<input type="reset" name="Reset" value="重置"> 
<input type="submit" name="Submit2" value="提交"> 
</p> 
</form> 
</body> 
</html> GetPostData.java
/*
 * Created on 2004-6-13
 *
 * To change the template for this generated file go to
 * Window - Preferences - Java - Code Generation - Code and Comments
 */
package com.servlet;import java.io.IOException;
import java.io.PrintWriter;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class GetPostData extends HttpServlet {
protected void processRequest(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
//TODO Method stub generated by Lomboz
//为解决编码问题后来添加
//response.setContentType("text/html;charset=gb2312"); 
     //request.setCharacterEncoding("gb2312");//解决编码问题 PrintWriter out = response.getWriter(); 
out.println( //a tools method to show the html code with title 
"<BODY BGCOLOR=\"#FDF5E6\">\n" + 
"<H1 ALIGN=CENTER>" + "get post data " + "</H1>\n" + 
"<UL>\n" + 
" <LI><B>username</B>: " 
+ request.getParameter("username") + "\n" + 
" <LI><B>password</B>: " 
+ request.getParameter("password") + "\n" + 
"</UL>\n" + 
"</BODY></HTML>");  }
        
        protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }    /** 
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }    /** 
     * Returns a short description of the servlet.
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <servlet>
        <servlet-name>First</servlet-name>
        <servlet-class>com.Servlet.First</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>GetPostData</servlet-name>
        <servlet-class>com.Servlet.GetPostData</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>First</servlet-name>
        <url-pattern>/First</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>GetPostData</servlet-name>
        <url-pattern>/GetPostData</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>
这是错误信息
HTTP Status 404 - --------------------------------------------------------------------------------

type Status reportmessagedescriptionThe requested resource () is not available.--------------------------------------------------------------------------------

解决方案 »

  1.   

    我改成这个了
    <form action="GetPostData" method ="post">
    但是出现新的错误HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessagedescriptionThe server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: PWC1381: Error allocating a servlet instance
    root cause java.lang.NoClassDefFoundError: com/Servlet/GetPostData (wrong name: com/servlet/GetPostData)
    note The full stack traces of the exception and its root causes are available in the GlassFish Server Open Source Edition 3.1 logs.
    --------------------------------------------------------------------------------GlassFish Server Open Source Edition 3.1那个action框里的就是我写的java名吗？但是改了还不对啊
      

  2.   

    java.lang.NoClassDefFoundError: com/Servlet/GetPostData (wrong name: com/servlet/GetPostData)你的路径是：/GetPostData
    但是这里的路径是：com/servlet/GetPostData
      

  3.   

    你的GetPostData.java我改成这样运行结果就正常了；
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
    // TODO Auto-generated method stub
    response.setContentType("text/html;charset=gb2312"); 
          request.setCharacterEncoding("gb2312");//解决编码问题
     
    PrintWriter out = response.getWriter(); 
     out.println( //a tools method to show the html code with title 
     "<BODY BGCOLOR=\"#FDF5E6\">\n" + 
     "<H1 ALIGN=CENTER>" + "get post data " + "</H1>\n" + 
     "<UL>\n" + 
     " <LI><B>username</B>: " 
     + request.getParameter("username") + "\n" + 
     " <LI><B>password</B>: " 
     + request.getParameter("password") + "\n" + 
     "</UL>\n" + 
     "</BODY></HTML>"); 
    } @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
    // TODO Auto-generated method stub
    this.doGet(request, response);
      

  4.   

    <form action="getpostdata" method ="post"> 和<url-pattern>/GetPostData</url-pattern>
    不一致，改成一致就可以了。
      

  5.   

     <servlet-mapping>
             <servlet-name>GetPostData</servlet-name>
             <url-pattern>/GetPostData</url-pattern>
         </servlet-mapping>
    <form action="getpostdata" method ="post"> 
    大小写不一致
    改：<form action="GetPostData" method ="post">