React Native 项目中执行 yarn android 命令运行项目，出现 Execution failed for task ':react-native-mmkv:downloadDoubleConversion'. ， javax.net.ssl.SSLException: Read timed out 等错误
如下效果
PS D:\code\AwesomeProject> yarn android yarn run v1.22.17 $ react-native run-android info Running jetifier to migrate libraries to AndroidX. You can disable it using "--no-jetifier" flag. Jetifier found 898 file(s) to forward-jetify. Using 16 workers... info Starting JS server... info Installing the app... > Task :react-native-mmkv:downloadBoost Download https://github.com/react-native-community/boost-for-react-native/releases/download/v1.63.0-0/boost_1_63_0.tar.gz > Task :react-native-mmkv:downloadDoubleConversion Download https://github.com/google/double-conversion/archive/v1.1.6.tar.gz > Task :react-native-mmkv:downloadDoubleConversion FAILED 43 actionable tasks: 28 executed, 15 up-to-date FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':react-native-mmkv:downloadDoubleConversion'. > javax.net.ssl.SSLException: Read timed out * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. * Get more help at https://help.gradle.org BUILD FAILED in 10m 33s error Failed to install the app. Make sure you have the Android development environment set up: https://reactnative.dev/docs/environment-setup. Error: Command failed: gradlew.bat app:installDebug -PreactNativeDevServerPort=8081 FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':react-native-mmkv:downloadDoubleConversion'. > javax.net.ssl.SSLException: Read timed out * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. * Get more help at https://help.gradle.org BUILD FAILED in 10m 33s at makeError (D:\code\AwesomeProject\node_modules\execa\index.js:174:9) at D:\code\AwesomeProject\node_modules\execa\index.js:278:16 at processTicksAndRejections (node:internal/process/task_queues:96:5) at async runOnAllDevices (D:\code\AwesomeProject\node_modules\@react-native-community\cli-platform-android\build\commands\runAndroid\runOnAllDevices.js:106:5) at async Command.handleAction (D:\code\AwesomeProject\node_modules\@react-native-community\cli\build\index.js:192:9) info Run CLI with --verbose flag for more details. error Command failed with exit code 1. info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
出现这种错误时，一般是由于下载对应文件超时导致的，例如上面的例子中 https://github.com/react-native-community/boost-for-react-native/releases/download/v1.63.0-0/boost_1_63_0.tar.gz 地址国内可能正常访问不了，需要配置 VPN 后才能正常访问，但是有时即使设置了 VPN 但是部分站点可能链接不稳定，也会导致下载失败。
解决方案
如果某个包下载失败，导致 yarn android 中止，如果在浏览器单独访问下载失败的包可以下载的，可以多次执行 yarn android 命令一次次把需要的包下载下来就可以了。
如果某个包下载失败，但是包的下载地址在浏览器中也不能访问，可以尝试调整 VPN 模式试试，如 VPN 的 Global，Rule，PAC 等模式对于包下载效果也不一样。
重点
React Native 日常开发有个稳定快速的 网络 和 VPN 太重要了。
