React 修改端口号

打开react项目的package.json文件
将 scripts中的start键值对
 "start": "react-scripts start"
 修改为
"scripts": {
  "start": "set PORT=9000 && react-scripts start","build": "react-scripts build","test": "react-scripts test --env=jsdom","eject": "react-scripts eject"
}