解決composer 下載錯誤

在windows環境下安裝完composer之後 使用composer命令下載 laravel5發現異常報錯了

  [Composer\Downloader\TransportException]
  The "http://packagist.org/packages.json" file could not be downloaded: failed to open stream: HTTP request failed!

create-project [-s|--stability="..."] [--prefer-source] [--prefer-dist] [--repository-url="..."] [--dev] [--no-dev] [--n
o-plugins] [--no-custom-installers] [--no-scripts] [--no-progress] [--keep-vcs] [--no-install] [--ignore-platform-reqs]
[package] [directory] [version]

百度一番之後 發現是被牆了！
更改composer配置切換到國內composer源
cmd下運行

composer config -l -g

在[home]配置項 得到composer配置路徑
修改config.json文件爲

{
    "config": {},
    "repositories": [
      {"type": "composer", "url": "http://pkg.phpcomposer.com/repo/packagist/"},
      {"packagist": false}
    ]
}

再次運行之前的composer下載laravel5命令

composer create-project laravel/laravel learnlaravel5 5.0.22

ok！