这个问题在这里已有答案：
我有PHP版本7，Windows 10 Pro OS，并且已经在php.ini中注入extension=php_intl.dll而没有评论。 （它首先没有;extension=php_intl.dll）
通过composer安装会显示以下错误：
您的要求无法解析为可安装的软件包集。
问题1
- cakephp/cakephp 3.6.9 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.8 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.7 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.6 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.5 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.4 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.3 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.2 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.10 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.1 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.6.0 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- Installation request for cakephp/cakephp 3.6.* -> satisfiable by cakephp/cakephp[3.6.0, 3.6.1, 3.6.10, 3.6.2, 3.6.3, 3.6.4, 3.6.5, 3.6.6, 3.6.7, 3.6.8, 3.6.9].
在php.ini文件中，取消注释以下行
;extension=php_intl.dll