Symfony2中的系统(SonataAdminBundle)中缺少所需的PHP扩展名intl

我尝试安装沙箱，但从composer收到以下错误:

I try to install the sandbox but I get the following error from composer:

使用软件包信息加载composer存储库安装 锁定文件中的依赖项您的要求无法解决 一整套可安装的软件包.

Loading composer repositories with package information Installing dependencies from lock file Your requirements could not be resolved to an installable set of packages.

问题1

- Installation request for sonata-project/intl-bundle 2.1.0 -> satisfiable by sonata-project/intl-bundle 2.1.0.`

- sonata-project/intl-bundle 2.1.0 requires ext-intl * -> the requested PHP extension intl is missing from your system.`

问题2

- sonata-project/intl-bundle 2.1.0 requires ext-intl * -> the requested PHP extension intl is missing from your system.`

- sonata-project/news-bundle 2.1.x-dev requires sonata-project/intl-bundle 2.1.* -> satisfiable by sonata-project/intl-bundle 2.1.0.
- Installation request for sonata-project/news-bundle 2.1.