Vue-cli3 $ is not defined错误问题及解决

npm install jquery --save

"dependencies": {
    "axios": "^0.18.0",
    "core-js": "^2.6.5",
    "jquery": "^3.5.1",
    "lrz": "^4.9.40",
    "moment": "^2.23.0",
    "qrcode2": "^1.2.3",
    "vant": "^2.2.16",
    "vue": "^2.6.10",
    "vue-router": "^3.0.3",
    "vuex": "^3.0.1"
  },

import $ from 'jquery'

npm run dev

npm install jquery --save
//		或者使用淘宝镜像
cnpm install jquery --save

var webpack = require('webpack')

 plugins: [ 
    new webpack.optimize.CommonsChunkPlugin('common.js'),
    new webpack.ProvidePlugin({
      jQuery: "jquery",
      $: "jquery" 
    }) 
  ]

var webpack = require('webpack')

module.exports = {
    lintOnSave: false,
    devServer: {
        proxy: {
            '/api': {
                target: 'http://localhost:8000', //建立本地服务器端口可能不一样
                changeOrigin: true,
                ws: true,
                pathRewrite: {
                    '^/api': ''
                }
            }
        }
    },
    configureWebpack: {
        plugins: [
            new webpack.ProvidePlugin({
                $: "jquery",
                jQuery: "jquery",
            })
        ]
    }
}

import $ from 'jquery'

Vue.config.productionTip = false
new Vue({
    router,
    store,
    $, //添加该行即可
    render: h => h(App)
}).$mount('#app')

createApp(App).use(router).use($).mount('#app')

dependencies": {
    "axios": "^0.21.1",
    "bootstrap": "^5.0.2",
    "bootstrap-vue": "^2.21.2",
    "core-js": "^3.6.5",
    "jquery": "^3.6.0",
    "vue": "^3.1.5",
    "vue-router": "^4.0.10"
  },