HTTP状态 500 - 内部服务器错误

类型 异常报告

消息 Servlet执行抛出一个异常

描述 服务器遇到一个意外的情况，阻止它完成请求。

例外情况

javax.servlet.ServletException: Servlet执行抛出一个异常
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

根本原因。

java.lang.NoClassDefFoundError: Could not initialize class utils.MybatisUtils
	dao.userdao.selectByUsername(userdao.java:8)
	service.userservice.checklogin(userservice.java:14)
	servlet.loginservlet.doPost(loginservlet.java:33)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

):注意 主要问题的全部 stack 信息可以在 server logs 里查看

相关代码：userdao

package dao;

import entity.User;
import utils.MybatisUtils;

public class userdao {
    public User selectByUsername(String username) {
        User user = (User) MybatisUtils.executeQuery(sqlSession -> sqlSession.selectOne("usermapper.selectByUsername",username));
        return  user;
    }
}

相关代码：userservice

package service;

import dao.rbacdao;
import dao.userdao;
import entity.User;
import service.exception.bussinessException;

import java.util.List;

public class userservice {
    private dao.userdao userdao=new userdao();
    private dao.rbacdao nodedao = new rbacdao();
    public User checklogin(String username, String password) {
        User user = userdao.selectByUsername(username);
        if (user == null) {
        throw new bussinessException("L001","用户名不存在");
        }
        if (!user.getPassword().equals(password)) {
            throw new bussinessException("L002", "密码错误");
        }
        return user;
    }
    public List  selectNodeByUserId(long userId) {
        List list = nodedao.selectnodebyuserid(userId);
        return list;
    }
}

相关代码：loginservlet

package servlet;


import com.alibaba.fastjson.JSON;
import entity.User;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import service.exception.bussinessException;
import service.userservice;
import utils.MybatisUtils;
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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

@WebServlet(name = "LoginServlet" , urlPatterns = "/check_login")
public class loginservlet extends HttpServlet {
    private service.userservice userservice=new userservice();

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Logger logger= LoggerFactory.getLogger(loginservlet.class);
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        Map<String, Object> result = new HashMap<>();
        try {
            User user = userservice.checklogin(username, password);
            HttpSession Session = request.getSession();
            Session.setAttribute("login_user",user);
            result.put("code", "0");
            result.put("message","success");
            result.put("redirect_url", "/index");
        } catch (bussinessException ex) {
            logger.error(ex.getMessage(),ex);
            result.put("code",ex.getCode());
            result.put("message", ex.getMessage());
        } catch (Exception ex) {
            logger.error(ex.getMessage(),ex);
            result.put("code",ex.getClass().getSimpleName());
            result.put("message", ex.getMessage());
        }
        String json=JSON.toJSONString(result);
        response.getWriter().println(json);
    }}