tomcat在浏览器运行时，报500状态

Question

执行登录的时候，产生如下错误

我查看网络显示如下

控制台显示如下所示:

项目所有代码如下：
UserMapper

package com.hotel.dao;

import com.hotel.entity.User;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

public interface UserMapper {
    @Select("select * from admin where username = #{username} and password = #{password}")
    User getUser(@Param("username") String username, @Param("password") String password);
}

User

package com.hotel.entity;

import lombok.Data;

@Data
public class User {
    int id;
    String username;
    String nickname;
    String password;
}

MainFilter

package com.hotel.filter;

import com.hotel.entity.User;
import jakarta.servlet.FilterChain;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpFilter;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;

import java.io.IOException;

@WebServlet("/*")
public class MainFilter extends HttpFilter {
    @Override
    protected void doFilter(HttpServletRequest req, HttpServletResponse res, FilterChain chain) throws IOException, ServletException {
        String url = req.getRequestURL().toString();
        if(!url.contains("/static/") && !url.endsWith("login")){
            HttpSession session = req.getSession();
            User user = (User) session.getAttribute("user");
            if(user == null){
                res.sendRedirect("login");
                return;
            }
        }
        chain.doFilter(req,res);
    }
}

UserServiceImpl

package com.hotel.service.impl;

import com.hotel.dao.UserMapper;
import com.hotel.entity.User;
import com.hotel.service.UserService;
import com.hotel.utils.MybatisUtil;
import jakarta.servlet.http.HttpSession;
import org.apache.ibatis.session.SqlSession;

public class UserServiceImpl implements UserService {

    @Override
    public boolean auth(String username, String password, HttpSession session){
        try (SqlSession sqlSession = MybatisUtil.getSession()){
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            User user = mapper.getUser(username, password);
            if(user == null) return false;
            session.setAttribute("user",user);
            return true;
        }
    }
}

UserService

package com.hotel.service;

import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;

public interface UserService {

    boolean auth(String username, String password, HttpSession session);
}

LoginServlet

package com.hotel.serviet;

import com.hotel.service.UserService;
import com.hotel.service.impl.UserServiceImpl;
import com.hotel.utils.ThymeleafUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.thymeleaf.context.Context;

import java.io.IOException;

@WebServlet("/login")
public class LoginServlet extends HttpServlet {

    UserService service;
    @Override
    public void init() throws ServletException{
        service = new UserServiceImpl() ;
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
        Context context = new Context();
        if(req.getSession().getAttribute("login-failure") != null){
            context.setVariable("failure",true);
            req.getSession().removeAttribute("login-failure");
        }
        ThymeleafUtil.process("login.html", context,resp.getWriter());
    }

    @Override
    protected void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
        String username =req.getParameter("username");
        String password =req.getParameter("password");
        String remember =req.getParameter("remember-me");
            if(service.auth(username,password,req.getSession())){
                resp.getWriter().write("Login Success!");
            }else {
                req.getSession().setAttribute("login-failure",new Object());
                this.doGet(req,resp);
            }
    }

}

MybaitsUtil

package com.hotel.utils;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;

public class MybatisUtil {
    private static SqlSessionFactory factory;
    static {
        try{
            factory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader("mybatis-config.xml"));
        }catch (IOException e){
            e.printStackTrace();
        }
    }

    public static SqlSession getSession(){
        return factory.openSession(true);
    }
}

ThymeleafUtil

package com.hotel.utils;

import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.IContext;
import org.thymeleaf.templateresolver.ClassLoaderTemplateResolver;

import java.io.Writer;

public class ThymeleafUtil {
    private static final TemplateEngine engine;
    static {
        engine = new TemplateEngine();
        ClassLoaderTemplateResolver r = new ClassLoaderTemplateResolver();
        r.setCharacterEncoding("UTF-8");
        engine.setTemplateResolver(r);
    }

    public static void process(String template, IContext context, Writer writer){
        engine.process(template,context,writer);
    }
}

login.html

<!DOCTYPE html>
<!--[if IE 8]> <html lang="en" class="ie8 no-js"> <![endif]-->
<!--[if IE 9]> <html lang="en" class="ie9 no-js"> <![endif]-->
<!--[if !IE]><!-->
<html lang="zxx" xmlns: th ="https://www.thymeleaf.org">
<!--<![endif]-->
<!-- Begin Head -->

<head>
    <title>酒店管理系统 - 登录</title>
    <meta charset="utf-8">
    <meta content="width=device-width, initial-scale=1.0" name="viewport">
    <meta name="description" content="">
    <meta name="keywords" content="">
    <meta name="author" content="">
    <meta name="MobileOptimized" content="320">
    <!--Start Style -->
    <link rel="stylesheet" type="text/css" href="static/css/fonts.css">
    <link rel="stylesheet" type="text/css" href="static/css/bootstrap.min.css">
    <link rel="stylesheet" type="text/css" href="static/css/auth.css">
</head>

<body>
    <div class="ad-auth-wrapper">
        <div class="ad-auth-box">
            <div class="row align-items-center">
                <div class="col-xl-6 col-lg-6 col-md-12 col-sm-12 col-12">
                    <div class="ad-auth-img">
                        <img src="static/picture/auth-img1.png" alt="">
                    </div>
                </div>
                <div class="col-xl-6 col-lg-6 col-md-12 col-sm-12 col-12">
                    <div class="ad-auth-content">
                        <form method="post" action="login">
                            <h2><span class="primary">你好，</span>欢迎!</h2>
                            <p th:unless="${failure}">请输入用户名和密码进行登录</p>
                            <p th:if="${failure}" style="color: red">您的用户名或密码输入错误</p>
                            <div class="ad-auth-form">
                                <div class="ad-auth-feilds mb-30">
                                    <input type="text" placeholder="用户名称" class="ad-input" name="username">
                                    <div class="ad-auth-icon">
                                        <svg xmlns="http://www.w3.org/2000/svg" viewbox="0 0 483.3 483.3"><path d="M424.3,57.75H59.1c-32.6,0-59.1,26.5-59.1,59.1v249.6c0,32.6,26.5,59.1,59.1,59.1h365.1c32.6,0,59.1-26.5,59.1-59.1    v-249.5C483.4,84.35,456.9,57.75,424.3,57.75z M456.4,366.45c0,17.7-14.4,32.1-32.1,32.1H59.1c-17.7,0-32.1-14.4-32.1-32.1v-249.5    c0-17.7,14.4-32.1,32.1-32.1h365.1c17.7,0,32.1,14.4,32.1,32.1v249.5H456.4z" data-original="#000000" class="active-path" data-old_color="#000000" fill="#9abeed"></path><path d="M304.8,238.55l118.2-106c5.5-5,6-13.5,1-19.1c-5-5.5-13.5-6-19.1-1l-163,146.3l-31.8-28.4c-0.1-0.1-0.2-0.2-0.2-0.3    c-0.7-0.7-1.4-1.3-2.2-1.9L78.3,112.35c-5.6-5-14.1-4.5-19.1,1.1c-5,5.6-4.5,14.1,1.1,19.1l119.6,106.9L60.8,350.95    c-5.4,5.1-5.7,13.6-0.6,19.1c2.7,2.8,6.3,4.3,9.9,4.3c3.3,0,6.6-1.2,9.2-3.6l120.9-113.1l32.8,29.3c2.6,2.3,5.8,3.4,9,3.4    c3.2,0,6.5-1.2,9-3.5l33.7-30.2l120.2,114.2c2.6,2.5,6,3.7,9.3,3.7c3.6,0,7.1-1.4,9.8-4.2c5.1-5.4,4.9-14-0.5-19.1L304.8,238.55z" data-original="#000000" class="active-path" data-old_color="#000000" fill="#9abeed"></path></svg>
                                    </div>
                                </div>
                                <div class="ad-auth-feilds">
                                    <input type="password" placeholder="密码" class="ad-input" name="password">
                                    <div class="ad-auth-icon">
                                        <svg xmlns="http://www.w3.org/2000/svg" viewbox="0 0 482.8 482.8"><path d="M395.95,210.4h-7.1v-62.9c0-81.3-66.1-147.5-147.5-147.5c-81.3,0-147.5,66.1-147.5,147.5c0,7.5,6,13.5,13.5,13.5    s13.5-6,13.5-13.5c0-66.4,54-120.5,120.5-120.5c66.4,0,120.5,54,120.5,120.5v62.9h-275c-14.4,0-26.1,11.7-26.1,26.1v168.1    c0,43.1,35.1,78.2,78.2,78.2h204.9c43.1,0,78.2-35.1,78.2-78.2V236.5C422.05,222.1,410.35,210.4,395.95,210.4z M395.05,404.6    c0,28.2-22.9,51.2-51.2,51.2h-204.8c-28.2,0-51.2-22.9-51.2-51.2V237.4h307.2L395.05,404.6L395.05,404.6z" data-original="#000000" class="active-path" data-old_color="#000000" fill="#9abeed"></path><path d="M241.45,399.1c27.9,0,50.5-22.7,50.5-50.5c0-27.9-22.7-50.5-50.5-50.5c-27.9,0-50.5,22.7-50.5,50.5    S213.55,399.1,241.45,399.1z M241.45,325c13,0,23.5,10.6,23.5,23.5s-10.5,23.6-23.5,23.6s-23.5-10.6-23.5-23.5    S228.45,325,241.45,325z" data-original="#000000" class="active-path" data-old_color="#000000" fill="#9abeed"></path></svg>
                                    </div>
                                </div>
                            </div>
                            <div class="ad-other-feilds">
                                <div class="ad-checkbox">
                                    <label>
                                    <input type="checkbox" name="remember-me" class="ad-checkbox">
                                    <span>记住我</span>
                                    </label>
                                </div>
                                <a class="forgot-pws-btn" href="#">忘记密码？</a>
                            </div>
                            <div class="ad-auth-btn">
                                <button class="ad-btn ad-login-member">登录</button>>
                            </div>
                            <p class="ad-register-text">没有用户吗? <a href="#">注册用户</a></p>
                        </form>
                    </div>
                </div>
            </div>
        </div>
    </div>
</body>

</html>

mybatis-configs.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/hotel_manage"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper class="com.hotel.dao.UserMapper"/>
    </mappers>
</configuration>

请问谁知道问题所在，可以告诉我吗？

Answer 1

MybatisUtil的factory应该初始化失败了，所以是null，调用oppenSeesion就会报空指针异常
你生成factory的时候用try catch了，所以查看一下你catch后e.printStackTrace的日志看看原因，估计是mybatis没配置好