add before (app) {.} to the devServer of webpack.dev.conf.js to deal with cross-domain problems. Get the data normally in the development environment. But the error is reported after compilation and packaging, so how does this code go into the configuration file of the production environment, and where is it placed? There is no such field as devserver in webpack.prod.conf.js. Ask God for help!

const devWebpackConfig = merge(baseWebpackConfig, {
  module: {
    rules: utils.styleLoaders({ sourceMap: config.dev.cssSourceMap, usePostCSS: true })
  },
  // cheap-module-eval-source-map is faster for development
  devtool: config.dev.devtool,

  // these devServer options should be customized in /config/index.js
  devServer: {
    clientLogLevel: "warning",
    historyApiFallback: {
      rewrites: [
        { from: /.*/, to: path.posix.join(config.dev.assetsPublicPath, "index.html") },
      ],
    },
    hot: true,
    contentBase: false, // since we use CopyWebpackPlugin.
    compress: true,
    host: HOST || config.dev.host,
    port: PORT || config.dev.port,
    open: config.dev.autoOpenBrowser,
    overlay: config.dev.errorOverlay
      ? { warnings: false, errors: true }
      : false,
    publicPath: config.dev.assetsPublicPath,
    before(app) {
      app.get("/api/getDisc", (req, res) => {
        let url = "https://c.y.qq.com/splcloud/fcgi-bin/fcg_get_diss_by_tag.fcg"
        axios.get(url, {
          headers: {
            referer: "https://y.qq.com"
          },
          params: req.query
        }).then((response) => {
          res.json(response.data)
        }).catch((e) => {
            console.log(e)
        })
      })
    },
    proxy: config.dev.proxyTable,
    quiet: true, // necessary for FriendlyErrorsPlugin
    watchOptions: {
      poll: config.dev.poll,
    }
  },