sdkmanager --update 失败的问题

flutter 安装遇到需要升级sdkmanager的问题

解决方法参考：https://blog.laji.cx/post/deal-with-android-sdkmanager-update-error/

https://stackoverflow.com/questions/46402772/failed-to-install-android-sdk-java-lang-noclassdeffounderror-javax-xml-bind-a

https://stackoverflow.com/questions/47150410/failed-to-run-sdkmanager-list-android-sdk-with-java-9

flutter官网解决方法：https://github.com/flutter/flutter/issues/28230

https://github.com/NativeScript/nativescript-cli/issues/3139

https://icetutor.com/question/failed-to-install-android-sdk-java-lang-noclassdeffounderror-javax-xml-bind-annotation-xmlschema/

总结： 一种是卸载高版本的jdk, 安装jdk8.0(建议)
一种就是修改sdkmanager的脚本