为什么我在快递中遇到404错误？我已经在视图和路线文件夹中正确创建了文件

注：最初它适用于signup.js，但现在更改了文件名后，它甚至显示了相同的错误。这是app.js代码：

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var bodyParser = require('body-parser');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var expressValidator = require('express-validator');
var expressSession = require('express-session');
var usersRouter = require('./routes/users');
var signup = require('./routes/sign_up');
var user_login = require('./routes/log_in');
var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(bodyParser.urlencoded({extended : true}));
app.use(bodyParser.json());
app.use(expressValidator());
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use(expressSession({secret:'max', saveUninitialized:false, resave: false}));
console.log(signup);
app.use('/', signup);
app.use('/users', usersRouter);
app.use('/login', user_login);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

这是log_in.js代码

var express = require('express');
var router = express.Router();
const mysql = require('mysql');

var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'root',
  password : 'abhiraj',
  database : 'nodelogin'
});
connection.connect((err) => {
  if (err) throw err;
  console.log('Connected!');
});

/* GET login page. */
router.get('/login', function(req, res, next) {
    res.render('log_in', { message: null });
   req.session.errors = null;
});

router.post('/auth', function(request, response) {
    var username = request.body.username;
    var password = request.body.password;
    connection.query('SELECT * FROM accounts WHERE username = ? AND password = ?', [username, password], function(error, results, fields) {
        if (results.length > 0){ 
            if(results[0].username===username && results[0].password===password)
                request.session.loggedin = true;
                request.session.username = username;
                response.send('Logged in');
               // response.redirect('/'+results[0].id);
                response.end();

        } else {
            console.log('incorrect-login');
            response.render('log_in', { message: "Incorrect Credentials" });
        }           
        response.end();
});
});

module.exports = router;

这是错误：

Not Found
404
NotFoundError: Not Found
    at c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\app.js:34:8
    at Layer.handle [as handle_request] (c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\layer.js:95:5)
    at trim_prefix (c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\index.js:317:13)
    at c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\index.js:284:7
    at Function.process_params (c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\index.js:335:12)
    at next (c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\index.js:275:10)
    at c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\index.js:635:15
    at next (c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\index.js:260:14)
    at next (c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\route.js:127:14)
    at Layer.handle [as handle_request] (c:\Users\Abhiraj Kale\Documents\JS\.vscode\Node.js\mysite\node_modules\express\lib\router\layer.js:91:12)

这是我的文件结构：

router.get('/login', function(req, res, next) {
    res.render('log_in', { message: null });
   req.session.errors = null;
});

正如我从app.js中看到的那样，您的中间件已经具有/ login。因此，您需要从快速路由器中删除/ login；

所以您的新代码应该是

 router.get('/', function(req, res, next) {
        res.render('log_in', { message: null });
       req.session.errors = null;
    });