1. npx 指定umi版本号安装

npx @umijs/create-umi-app@3.4.25

之后用

yarn 

安装项目依赖

2. 高版本nodejs下，跑项目会出异常:

Starting the development server...

* Webpack █████████████████████████ building (10%) 1/2 modules 1 active
 ...odules\umi\node_modules\@umijs\preset-built-in\bundled\@pmmmwh\react-refresh-webpack-plugin\client\ReactRefreshEnt
ry.js

node:internal/crypto/hash:71
  this[kHandle] = new _Hash(algorithm, xofLen);
                  ^

Error: error:0308010C:digital envelope routines::unsupported
    at new Hash (node:internal/crypto/hash:71:19)
    at Object.createHash (node:crypto:133:10)
    at module.exports.__webpack_modules__.57442.module.exports (G:\React Project\LeApp3x\node_modules\@umijs\deps\compiled\webpack\4\bundle4.js:135907:62)
    at NormalModule._initBuildHash (G:\React Project\LeApp3x\node_modules\@umijs\deps\compiled\webpack\4\bundle4.js:109317:16)
    at handleParseError (G:\React Project\LeApp3x\node_modules\@umijs\deps\compiled\webpack\4\bundle4.js:109371:10)
    at G:\React Project\LeApp3x\node_modules\@umijs\deps\compiled\webpack\4\bundle4.js:109403:5
    at G:\React Project\LeApp3x\node_modules\@umijs\deps\compiled\webpack\4\bundle4.js:109258:12
    at G:\React Project\LeApp3x\node_modules\@umijs\deps\compiled\webpack\4\bundle4.js:61157:3
    at iterateNormalLoaders (G:\React Project\LeApp3x\node_modules\@umijs\deps\compiled\webpack\4\bundle4.js:60998:10)
    at Array.<anonymous> (G:\React Project\LeApp3x\node_modules\@umijs\deps\compiled\webpack\4\bundle4.js:60989:4) {
  opensslErrorStack: [ 'error:03000086:digital envelope routines::initialization error' ],
  library: 'digital envelope routines',
  reason: 'unsupported',
  code: 'ERR_OSSL_EVP_UNSUPPORTED'

修复方法：
在项目目录下:

$env:NODE_OPTIONS="--openssl-legacy-provider"

之后项目就能正常跑了

Starting the development server...

√ Webpack
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 DONE  Compiled successfully in 17629ms