Java Web项目错误，一直找不出原因

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>login</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <description></description>
    <display-name>IndexServlet</display-name>
    <servlet-name>IndexServlet</servlet-name>
    <servlet-class>servlet.IndexServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>IndexServlet</servlet-name>
    <url-pattern>/IndexServlet</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>LoginServlet</display-name>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>servlet.LoginServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/LoginServlet</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>LogoutServlet</display-name>
    <servlet-name>LogoutServlet</servlet-name>
    <servlet-class>servlet.LogoutServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LogoutServlet</servlet-name>
    <url-pattern>/LogoutServlet</url-pattern>
  </servlet-mapping>
</web-app>

package servlet;

import java.io.IOException;
import java.io.PrintWriter;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;

import bean.User;

/**
 * Servlet implementation class LoginServlet
 */
public class LoginServlet extends HttpServlet {
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out = response.getWriter();
		// 获取用户名密码
		String username = request.getParameter("username");
		String password = request.getParameter("password");
		if ("itcast".equals(username) && "123".equals(password)) {
			//认证成功，跳转到主页，并且把登录记录添加到session中保存
			HttpSession session = request.getSession();
			//session中保存的是登录记录，即登录信息，所以把用户信息放入session中
			User user = new User(username, password);
			session.setAttribute("isLogin", user);
			response.sendRedirect("/login/IndexServlet");
		} else {
			out.println("用户名密码错误");
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		this.doGet(request, response);
	}

}

package servlet;

import java.io.IOException;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;

/**
 * Servlet implementation class LogoutServlet
 */
public class LogoutServlet extends HttpServlet {

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		// 清除登录记录，即清除session中的isLogin用户记录
		HttpSession session = request.getSession();
		session.removeAttribute("isLogin");
		// 重定向到首页
		response.sendRedirect("/login/IndexServlet");	
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		this.doGet(request, response);
	}

}

package servlet;

import java.io.IOException;
import java.io.PrintWriter;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;

import bean.User;

/**
 * Servlet implementation class IndexServlet
 */
public class IndexServlet extends HttpServlet {

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		// 获取登录记录，看用户是否登录
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out = response.getWriter();
		HttpSession session = request.getSession();
		// 根据session中的isLogin名字获取登录记录中对象信息
		User user = (User) session.getAttribute("isLogin");
		if (user == null) {
			// 没有用户信息，跳转登录
			String url = "/login/login.html";
			out.println("当前没登录，请登录<a href = '" + url +  "'>登录页面</a>");
		} else {
			
			String logoutUrl = "/login/LogoutServlet";
			out.println("欢迎：" + user.getUsername() + "登录     <a href='" + logoutUrl +"'>退出</a>");
			// 有用户信息，则将存有用信息的sessionId发给前端
			Cookie cookie = new Cookie("JSESSIONID", session.getId());
			response.addCookie(cookie);
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		this.doGet(request, response);
	}

}

<!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=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<form name="reg" action="/login/LoginServlet" method="post">
		用户名: <input name="username" type="text" /><br/>
		密&nbsp;&nbsp;码：<input name="password" type="password" /><br/>	
			    <input type="submit" value="提交" id="bt" />
	</form>
</body>
</html>

上面是代码，账户是itcast，密码是123，localhost:8080/login/login.html运行是成功的，可以输入账户密码，但是当输入账户密码点击提交后就会报404错误，但是eclipse上没有显示代码段有任何的错误

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