composer install the specified version of ThinkPHP

composer default official repositories in a foreign country, if not over the wall download speed is very slow.

There are two methods by composer mounting ThinkPHP:

The first:

composer create-project topthink / think [ : version] <installation path> 
Composer Create-topthink Project / Think: 5.1.20 ThinkPHP_5.1.20

The second:

Create composer.json file and then "composer install" to install.