text: 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 index = require('./routes/index');     //import index module
  var users = require('./routes/users');     //import users module
  
  var app = express();  //creates an express application
  
  // view engine setup
  // assign setting name to value,if name is one of the application settings,it affects the behavior of the application.
  app.set('views', path.join(__dirname, 'views'));  //official:A directory or an array of directories for the application's views
  app.set('view engine', 'ejs');  //official:The default engine extension to use when omitted.
  
  // uncomment after placing your favicon in /public
  //app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
  //Mounts the middleware function(s) at the path,if path is not specified,it defaults to '/'.
  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')));   //该文件中的文件为静态文件，可以直接拿访问
  app.use(express.static('public'));  //托管静态文件
  // app.use('/static',express.static('public'));  //如果需要访问的文件都放在一个虚拟的目录下面，即可以用这种方法
  
  app.use('/', index);
  // app.use('/login', login);
  app.use(function(req,res,next){
      console.log('Time: %d', Date.now());
      next();
  });
  //
  app.use('/users', users);
  
  // 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 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;
  