Http404错误！急求解决办法~各位帮帮忙哈`

Y0328 2012-03-14 03:56:24

我建立的目录如下D:\Tomcat\apache-tomcat-6.0.35\webapps\02;02文件夹中有：welcome.html和WEB-INF文件夹；WEB-INF中有web.xml和classes；classes中有WelcomeServlet.java和WelcomeServlet.class

welcome.html内容 :
<html>
<head>
<title>欢迎您！</title>
</head>
<body>
<form action="welcome" method="get">
请输入用户名：<input type="text" name="username"><br>
<input type="submit" value="提交">
</form>
</body>
</html>

WelcomeServlet.java内容：
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 WelcomeServlet extends HttpServlet
{
private String greeting;
public void init()
{greeting=getInitParameter("greeting");}
public void DoGet(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException
{
req.setCharacterEncoding("gb2312");
String username=req.getParameter("username");
String welcomeInfo=greeting+", "+username;
resp.setContentType("text/html");
PrintWriter out=resp.getWriter();
out.println("<html><head><title>");
out.println("Welcome Page");
out.println("</head></title>");
out.println("<body>");
out.println(welcomeInfo);
out.println("</body></html>");
out.close();
}

}

web.xml内容：
<?xml version="1.0" encoding="ISO-8859-1"?>


<web-app 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"
version="2.5">

<servlet>
<servlet-name>HelloServlet</servlet-name>
<servlet-class>HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloServlet</servlet-name>
<url-pattern>/helloservlet</url-pattern>
</servlet-mapping>

<servlet>
<servlet-name>WelcomeServlet</servlet-name>
<servlet-class>WelcomeServlet</servlet-class>
<init-param>
<param-name>greeting</param-name>
<param-value>Welcome you</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>WelcomeServlet</servlet-name>
<url-pattern>/welcome</url-pattern>
</servlet-mapping>

</web-app>

WelcomeServlet.java编译通过，在浏览器地址中输入：http://localhost:8080/02/welcome.html，显示出网页并输入相关数据后，点击“提交”按钮却出现一个错误页，错误页如下：

HTTP Status 404 - Servlet WelcomeServlet is not available

--------------------------------------------------------------------------------

type Status report

message Servlet WelcomeServlet is not available

description The requested resource (Servlet WelcomeServlet is not available) is not available.

--------------------------------------------------------------------------------

Apache Tomcat/6.0.35

请各位帮帮忙啊~~~万分感谢！！！

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