我对docker不太熟悉，但是它听起来您的设置是这样的：您的docker实例正在虚拟机中运行，并且您正尝试从Windows计算机访问绑定到localhost（即vm）的应用程序。您会在curl上被拒绝的原因是，实际上在主机（Windows）的端口4000上没有监听。

I'm not very familiar with docker, but it sounds like your setup is such that your docker instance is running in a virtual machine, and you're trying to access an application bound to localhost (the vm) from your Windows machine. The reason you would get a refusal here from curl is because nothing is actually listening on port 4000 on the host (Windows).

尝试通过以下方式查找您的Docker实例正在使用的IP：

Try to find the IP that your docker instance is using by:

$ docker-machine ip default

现在您知道IP地址，请再次尝试curl。您甚至可以像下面这样在命令中对其进行求值：

Now that you know the IP address, try curl again. You can even have it evaluated within the command like so:

$ curl http：// $（docker-machine ip默认值）：4000