1. supervisor
Node Supervisor is used to restart programs when they crash.
Node Supervisor 是用来当程序崩溃时重启的。
It can also be used to restart programs when a .js file changes.
它也可以用来重启程序，当.js文件发生改变。
2. pm2
PM2 is a production process manager for Node.js applications with a built-in load balancer. It allows you to keep applications alive forever, to reload them without downtime and to facilitate common system admin tasks.
PM2是一个针对Node.js应用的产品进程管理器。它帮助你保持应用永远存活。
3.http-server
一个命令行启动的http服务器