默认系统监听 127.0.0.1

			
var port = process.env.PORT || 8000;  
app.listen(port, '0.0.0.0');
			
			

			
var allowCrossDomain = function(req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
    res.header('Access-Control-Allow-Headers', 'Content-Type');

    next();
}

app.use(allowCrossDomain);