vue-element-admin配置后端接口解决跨域问题

1. 修改 .env.development文件
   添加VUE_APP_BASE_DOMAIN和VUE_APP_BASE_API

# just a flag
ENV = 'development'

# base api
# VUE_APP_BASE_API = '/dev-api'
VUE_APP_BASE_DOMAIN = 'http://www.xxxx.com'
VUE_APP_BASE_API = '/admin-api'

说明：VUE_APP_BASE_DOMAIN为接口域名地址,VUE_APP_BASE_API为域名后面的接口前缀<这个在页面审查元素看到，可以和实际的接口前缀不同>

2. 修改vue.config.js文件
   在devServer下面添加proxy并注释掉before: require(‘./mock/mock-server.js’)

module.exports = {
  /**
   * You will need to set publicPath if you plan to deploy your site under a sub path,
   * for example GitHub Pages. If you plan to deploy your site to https://foo.github.io/bar/,
   * then publicPath should be set to "/bar/".
   * In most cases please use '/' !!!
   * Detail: https://cli.vuejs.org/config/#publicpath
   */
  publicPath: '/',
  outputDir: 'dist',
  assetsDir: 'static',
  lintOnSave: process.env.NODE_ENV === 'development',
  productionSourceMap: false,
  devServer: {
    port: port,
    open: true,
    overlay: {
      warnings: false,
      errors: true
    },
    proxy: {
      [process.env.VUE_APP_BASE_API]: {
        target: process.env.VUE_APP_BASE_DOMAIN,
        changeOrigin: true,  //配置跨域
        ws: true,
        pathRewrite: {
          ['^' + process.env.VUE_APP_BASE_API]: '/admin-api'

        }
      }
    }
    // before: require('./mock/mock-server.js')
  },

3. 重新执行npm run dev, 接口请求成功