MyEclipse里JSP Servlet 里action 出错啊

这个是书上的例子, 调试不通过, 很菜的说 :

index.jsp

<form action="LoginServlet" method="post">

用户名：<input type="text" name="username"/><br/>
密码：<input type="text" name="password"/><br/>
<input type="submit" value="登陆"/><input type="reset" value="重置"/>
</form>
----------------------------------------------------------------------

LoginServlet.java 这样

package test.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;

import test.model.LoginModel;
public class LoginServlet extends HttpServlet{
......
}

编译都通过了,

但是一运行点index.jsp里的登陆 ,就出现 错误如下

HTTP Status 404 - /JSPSJB/LoginServlet

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

type Status report

message /JSPSJB/LoginServlet

description The requested resource (/JSPSJB/LoginServlet) is not available.


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

Apache Tomcat/6.0.13


啥问题啊 ,谢谢
[解决办法]

引用:

咋配置啊,
<?xml version="1.0" encoding="UTF-8" ?>
- <web-app version="3.0" 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_3_0.xsd">
<display-name />
- <welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

<code>
<servlet>
<servlet-name>HelloWorldServlet</servlet-name>
<servlet-class>HelloWorldServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorldServlet</servlet-name>
<url-pattern>/HelloWorldServlet/*</url-pattern>
</servlet-mapping>
</code>