404.。

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         id="WebApp_ID" version="3.1">
    <display-name>mybatispro</display-name>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>home.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>

</web-app>

UsersFindServlet

package com.damu.servlet;

import com.damu.dao.UsersDao;
import com.damu.entity.Users;


import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;


@WebServlet("/index")
public class UsersFindServlet extends HttpServlet {
    private UsersDao usersDao=new UsersDao();
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        List<Users> list=usersDao.findAll();
        req.setAttribute("usersList",list);
        req.getRequestDispatcher("index.jsp").forward(req,resp);
    }
}

UsersDao

package com.damu.dao;

import com.damu.entity.Users;
import com.damu.utils.SqlSessionFactoryUtils;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import java.util.List;

public class UsersDao {
    private SqlSession sqlSession=SqlSessionFactoryUtils.getSqlSessionFactory().openSession();
    private List<Users> list;
    public List<Users>findAll(){

        try {
            list=sqlSession.selectList("findAll");

        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            sqlSession.close();
        }
        return list;
    }
}