Javascript 文件上传返回"；“未定义”；

因此，我使用的是Express File Upload，当我尝试向其发送post请求时，它会从设置的错误处理程序返回错误，当我

console.log（req.files）

返回未定义的错误时，它基本上找不到任何文件，这就是为什么会返回错误，但我不知道如何解决这个问题

Index.js

router.post('/upload-avatar', async (req, res) => {
  try {
    console.log(req.files)
    if(!req.files) {
      res.send({
        status: false,
        message: 'No file uploaded'
      });
    } else {
      //Use the name of the input field (i.e. "avatar") to retrieve the uploaded file
      let avatar = req.files.avatar;

      //Use the mv() method to place the file in upload directory (i.e. "uploads")
      avatar.mv('./uploads/' + avatar.name);

      //send response
      res.send({
        status: true,
        message: 'File is uploaded',
        data: {
          name: avatar.name,
          mimetype: avatar.mimetype,
          size: avatar.size
        }
      });
    }
  } catch (err) {
    res.status(500).send(err);
  }
});

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');


const fileUpload = require('express-fileupload');
const cors = require('cors');
const bodyParser = require('body-parser');
const _ = require('lodash');

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');

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(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', indexRouter);
app.use('/users', usersRouter);

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



app.use(fileUpload({
  createParentPath: true
}));
app.use(cors());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));


// 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;

App.js

router.post('/upload-avatar', async (req, res) => {
  try {
    console.log(req.files)
    if(!req.files) {
      res.send({
        status: false,
        message: 'No file uploaded'
      });
    } else {
      //Use the name of the input field (i.e. "avatar") to retrieve the uploaded file
      let avatar = req.files.avatar;

      //Use the mv() method to place the file in upload directory (i.e. "uploads")
      avatar.mv('./uploads/' + avatar.name);

      //send response
      res.send({
        status: true,
        message: 'File is uploaded',
        data: {
          name: avatar.name,
          mimetype: avatar.mimetype,
          size: avatar.size
        }
      });
    }
  } catch (err) {
    res.status(500).send(err);
  }
});

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');


const fileUpload = require('express-fileupload');
const cors = require('cors');
const bodyParser = require('body-parser');
const _ = require('lodash');

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');

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(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', indexRouter);
app.use('/users', usersRouter);

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



app.use(fileUpload({
  createParentPath: true
}));
app.use(cors());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));


// 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;

我正在使用azure服务器，目前我正在使用postman使其首先工作

---

提前谢谢

应适当订购中间件。文件上载中间件位于索引路由器下方。因此，当请求到达服务器Express时，将在上载中间件之前运行indexRouter的处理程序，除非处理程序调用

next（）

，否则文件上载中间件将不会处理您的请求。您不能调用

next（）

，因为这意味着“我的部分已经完成，请将此请求（req）交给下一个中间件/处理程序”

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');


const fileUpload = require('express-fileupload');
const cors = require('cors');
const bodyParser = require('body-parser');
const _ = require('lodash');

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');

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(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use(fileUpload({
  createParentPath: true
}));
app.use(cors());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));

app.use('/', indexRouter);
app.use('/users', usersRouter);

// 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;

---

尝试移动

应用程序。使用（“/”，indexRouter）行就在错误处理程序中间件之前。它只是返回一个404错误，表示找不到该页