未處理的“錯誤”事件？

Question

當我添加所有三個文件（app.js中的dishRouter.js，promoRouter.js和leaderRouter.js）時，出現以下錯誤

錯誤圖片

這是我的app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var routes = require('./routes/index');
var users = require('./routes/users');
var dishRouter = require('./routes/dishRouter');
var promoRouter = require('./routes/promoRouter');
var leaderRouter = require('./routes/leaderRouter');

var app = express();

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

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));

app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());

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

app.use('/', routes);
app.use('/users', users);
app.use('/dishes',dishRouter);
app.use('/promotions',promoRouter);
app.use('/leadership',leaderRouter);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handlers
// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});

module.exports = app;

這是dishRouter.js

var express = require('express');
var morgan = require('morgan');
var bodyParser = require('body-parser');

var hostname = 'localhost';
var port = 3000;

var app = express();

app.use(morgan('dev'));

var dishRouter = express.Router();

dishRouter.use(bodyParser.json());

dishRouter.route('/')
.all(function(req,res,next) {
      res.writeHead(200, { 'Content-Type': 'text/plain' });
      next();
})

.get(function(req,res,next){
        res.end('Will send all the dishes to you!');
})

.post(function(req, res, next){
    res.end('Will add the dish: ' + req.body.name + ' with details: ' + req.body.description);
})

.delete(function(req, res, next){
        res.end('Deleting all dishes');
});

dishRouter.route('/:dishId')
.all(function(req,res,next) {
      res.writeHead(200, { 'Content-Type': 'text/plain' });
      next();
})

.get(function(req,res,next){
        res.end('Will send details of the dish: ' + req.params.dishId +' to you!');
})

.put(function(req, res, next){
        res.write('Updating the dish: ' + req.params.dishId + '\n');
    res.end('Will update the dish: ' + req.body.name +
        ' with details: ' + req.body.description);
})

.delete(function(req, res, next){
        res.end('Deleting dish: ' + req.params.dishId);
});

app.use('/dishes',dishRouter);

app.use(express.static(__dirname + '/public'));

app.listen(port, hostname, function(){
  console.log(`Server running at http://${hostname}:${port}/`);
});

module.exports = dishRouter;

這是leaderRouter.js

var express = require('express');
var morgan = require('morgan');
var bodyParser = require('body-parser');

var hostname = 'localhost';
var port = 3000;

var app = express();

app.use(morgan('dev'));

var leaderRouter = express.Router();

leaderRouter.use(bodyParser.json());

leaderRouter.route('/')
.all(function(req,res,next) {
      res.writeHead(200, { 'Content-Type': 'text/plain' });
      next();
})

.get(function(req,res,next){
        res.end('Will send all the leaders to you!');
})

.post(function(req, res, next){
    res.end('Will add the leader: ' + req.body.name + ' with details: ' + req.body.description);
})

.delete(function(req, res, next){
        res.end('Deleting all leaders');
});

leaderRouter.route('/:leaderId')
.all(function(req,res,next) {
      res.writeHead(200, { 'Content-Type': 'text/plain' });
      next();
})

.get(function(req,res,next){
        res.end('Will send details of the leader: ' + req.params.leaderId +' to you!');
})

.put(function(req, res, next){
        res.write('Updating the leader: ' + req.params.leaderId + '\n');
    res.end('Will update the leader: ' + req.body.name +
        ' with details: ' + req.body.description);
})

.delete(function(req, res, next){
        res.end('Deleting leader: ' + req.params.leaderId);
});

app.use('/leaders',leaderRouter);

app.use(express.static(__dirname + '/public'));

app.listen(port, hostname, function(){
  console.log(`Server running at http://${hostname}:${port}/`);
});

module.exports = leaderRouter;

這是promoRouter.js

var express = require('express');
var morgan = require('morgan');
var bodyParser = require('body-parser');

var hostname = 'localhost';
var port = 3000;

var app = express();

app.use(morgan('dev'));

var promoRouter = express.Router();

promoRouter.use(bodyParser.json());

promoRouter.route('/')
.all(function(req,res,next) {
      res.writeHead(200, { 'Content-Type': 'text/plain' });
      next();
})

.get(function(req,res,next){
        res.end('Will send all the promotions to you!');
})

.post(function(req, res, next){
    res.end('Will add the promotion: ' + req.body.name + ' with details: ' + req.body.description);
})

.delete(function(req, res, next){
        res.end('Deleting all promotions');
});

promoRouter.route('/:promotionId')
.all(function(req,res,next) {
      res.writeHead(200, { 'Content-Type': 'text/plain' });
      next();
})

.get(function(req,res,next){
        res.end('Will send details of the promotion: ' + req.params.promotionId +' to you!');
})

.put(function(req, res, next){
    res.write('Updating the promotion: ' + req.params.promotionId + '\n');
    res.end('Will update the promotion: ' + req.body.name +
        ' with details: ' + req.body.description);
})

.delete(function(req, res, next){
        res.end('Deleting promotion: ' + req.params.promotionId);
});

app.use('/promotions',promoRouter);

app.use(express.static(__dirname + '/public'));

app.listen(port, hostname, function(){
  console.log(`Server running at http://${hostname}:${port}/`);
});

module.exports = promoRouter;

但是只添加一個路由器，效果很好，為什么呢？

我使用Win7，節點v4.4.5，npm v3.9.0

Answer 1

在每個路由器中，您都呼叫app.listen 。 這就是啟動Express服務器在該端口上偵聽的原因。 它可以在第一個路由器上運行，但是在第二個路由器上，它將引發錯誤，告訴您該端口正在使用中。 只有一個應用程序可以在特定端口上偵聽。 正確的方法是從各個路由器中刪除所有常見的東西，並將它們放入您的app.js

Answer 2

右刪除app.listen（）使服務器成功運行。 但是，服務器會通過404消息用代碼響應對路由腳本的請求。

在下面的鏈接中嘗試了以下路由代碼

https://gist.github.com/MCheli/c4efc94f0d754f3e497e13b1bbf04b0d

和下面的服務器代碼

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var routes = require('./routes/index');
var users = require('./routes/users');
var dishRouter = require('./routes/dishRouter');
var promoRouter = require('./routes/promoRouter');
var leaderRouter = require('./routes/leaderRouter');

var app = express();

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

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));

app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());

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

app.use('/', routes);
app.use('/users', users);
app.use('/dishes',dishRouter);
app.use('/promotions',promoRouter);
app.use('/leadership',leaderRouter);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});

// error handlers
// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
  message: err.message,
  error: err
});
});
}

// production error handler
// no stacktraces leaked to userfor the server.js file
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});

module.exports = app;