WELL ，Finally, I successfully downloaded the system files through the composer under Windows 2012 R2 by following step:
- Find and enter the PHP installation directory (the same set of PHP instructions you execute on the command line).
- Copy composer.phar to the PHP installation directory, which is the same directory as php.exe.
- Create a new composer.bat file in the PHP installation directory, and save the following code to this file.
@php "%~dp0composer.phar" %*
composer create-project flarum/flarum . --stability=beta
Five minutes later, I finally saw the public directory and other files. I'm so happy about it!
Plugin installation failed, rolling back
after 8min installing started...
SET ./PUBLIC AS webroot
JOB Done! THANK YOU VERY MUCH FOR ALL OF YOU!
clarkwinkelmann @luceos @jordanjay29 @noitamerd