*我正在运行Windows 10 .

我打开cmd并输入：

composer create-project laravel/laravel **project_name**

我在cmd中得到以下行：

You are running Composer with SSL/TLS protection disabled.
Loading composer repositories with package information

但它似乎一切都很好，文件夹结构是正确的 .

然后我键入以下commnad以下载我的所有dependecies [vendor dir]：

composer install

我在cmd中获得以下行：

您正在运行已禁用SSL / TLS保护的Composer . 使用包信息加载composer存储库警告：通过http访问packagist.org这是一种不安全的协议 . 更新依赖项（包括require-dev）无法将您的需求解析为可安装的软件包集 .

Problem 1
    - laravel/framework v5.4.9 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.8 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.7 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.6 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.5 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.4 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.28 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.27 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.26 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.25 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.24 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.23 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.22 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.21 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.20 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.2 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.19 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.18 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.17 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.16 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.15 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.14 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.13 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.12 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.11 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.10 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.1 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.4.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - Installation request for laravel/framework 5.4.* -> satisfiable by laravel/framework[v5.4.0, v5.4.1, v5.4.10, v5.4.11, v5.4.12, v5.4.13, v5.4.14, v5.4.15, v5.4.16, v5.4.17, v5.4.18, v5.4.19, v5.4.2, v5.4.20, v5.4.21, v5.4.22, v5.4.23, v5.4.24, v5.4.25, v5.4.26, v5.4.27, v5.4.28, v5.4.3, v5.4.4, v5.4.5, v5.4.6, v5.4.7, v5.4.8, v5.4.9].

它之前从未发生过我无法在这里或谷歌找到解决方案 . 谢谢 .

PS

我重新安装php到C：/ php我将php.ini文件解压缩到C：/ i设置环境变量，我也取消注释了扩展名