Failed opening required ' bootstrap/. /vendor/autoload.php '

Cloning from the GIT version of the Library Laravel project, forget the composer install, the results of the following error ~

PHP Fatal Error:  require (): Failed opening required '/bcc/production/bccadminv1.0/bootstrap/. /vendor/autoload.php ' (include_path= '.:/ Usr/share/php ') in

Run:
Composer Install
The result was an error:

ubuntu@ip-172-31-4-119:$ composer install Loading composer repositories with package Information installing dependencies (including Require-dev) from lock file Your requirements could not is resolved to a I

  Nstallable set of packages.
    Problem 1-installation Request for Doctrine/instantiator 1.1.0-> satisfiable by doctrine/instantiator[1.1.0].
  -Doctrine/instantiator 1.1.0 requires PHP ^7.1-> your PHP version (7.0.22) does not satisfy that requirement. Problem 2-doctrine/instantiator 1.1.0 requires PHP ^7.1-> your PHP version (7.0.22) does not satisfy
    Ement. -Phpunit/phpunit-mock-objects 2.3.8 requires Doctrine/instantiator ^1.0.2-> by satisfiable 1.1.0].-Installation request for Phpunit/phpunit-mock-objects 2.3.8-> satisfiable by Phpunit/phpunit-mock-object

S[2.3.8]. ubuntu@ip-172-31-4-119:$ ll 

My PHP version is too low, there is a package requirements are PHP version of more than 7.1 my 7.0.22, there are two solutions, one is to ignore:

Composer Install--ignore-platform-reqs

The second is to delete Composer.lock directly, I moved it directly to another place.

Then again:Composer Install

Visit the website again, it's OK.