在package.json的scripts中加上
“dev”: “set NODE_OPTIONS=–openssl-legacy-provider && vue-cli-service serve”

{
  "name": "vue-app",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "dev": "set NODE_OPTIONS=--openssl-legacy-provider && vue-cli-service serve"

  },
  "dependencies": {
    "core-js": "^3.6.5",
    "element-ui": "^2.15.1",
    "vue": "^2.6.11",
    "vue-router": "^3.2.0"
  },
  "devDependencies": {
    "@vue/cli-plugin-babel": "~4.5.0",
    "@vue/cli-plugin-router": "~4.5.0",
    "@vue/cli-service": "~4.5.0",
    "vue-template-compiler": "^2.6.11"
  },
  "browserslist": [
    "> 1%",
    "last 2 versions",
    "not dead"
  ]
  
}

然后运行下面命令即可

npm run dev