您的需求无法解析为可安装的一组软件包。 （Laravel）

Question

我试图安装laravel和应用命令

作曲家创建项目--prefer - 距离laravel/laravel博客

我碰到下面的错误，有什么能说，它是？

Problem 1 
    - laravel/framework v5.2.9 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.8 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.7 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.6 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.5 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.43 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.42 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.40 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.4 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.39 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.38 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.37 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.36 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.35 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.34 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.33 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.32 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.31 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.30 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.29 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.28 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.27 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.26 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.25 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.24 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.23 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.22 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.21 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.20 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.2 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.19 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.18 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.17 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.16 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.15 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.14 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.13 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.12 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.11 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.10 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.1 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework v5.2.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - laravel/framework 5.2.41 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. 
    - Installation request for laravel/framework 5.2.* -> satisfiable by laravel/framework[5.2.41, v5.2.0, v5.2.1, v5.2.10, 

v5.2.11，v5.2.12，v5.2.13，v5.2.14，v5.2.15，v5.2.16，v5.2.17， v5.2.18，v5.2.19，v5.2.2， v5.2.20，v5.2.21，v5.2.22，v5.2.23，v5.2.24, v5.2.25，v5.2.26，v5.2.27，v5.2.28，v5.2.29，v5.2.3，v5.2.30，v5 .2.31, v5.2.32，v5.2.33，v5.2.34，v5.2.35，v5.2.36，v5.2.37，v5.2.38, v5.2.39，v5.2.4，v5.2.40，v5.2.42，v5 .2.43，v5.2.5，v5.2.6，v5.2.7， v5.2.8，v5.2.9]。

To enable extensions, verify that they are enabled in those .ini files: 
    - /etc/php/7.0/cli/php.ini 
    - /etc/php/7.0/cli/conf.d/10-mysqlnd.ini 
    - /etc/php/7.0/cli/conf.d/10-opcache.ini 
    - /etc/php/7.0/cli/conf.d/10-pdo.ini 
    - /etc/php/7.0/cli/conf.d/20-calendar.ini 
    - /etc/php/7.0/cli/conf.d/20-ctype.ini 
    - /etc/php/7.0/cli/conf.d/20-exif.ini 
    - /etc/php/7.0/cli/conf.d/20-fileinfo.ini 
    - /etc/php/7.0/cli/conf.d/20-ftp.ini 
    - /etc/php/7.0/cli/conf.d/20-gettext.ini 
    - /etc/php/7.0/cli/conf.d/20-iconv.ini 
    - /etc/php/7.0/cli/conf.d/20-json.ini 
    - /etc/php/7.0/cli/conf.d/20-mcrypt.ini 
    - /etc/php/7.0/cli/conf.d/20-mysqli.ini 
    - /etc/php/7.0/cli/conf.d/20-pdo_mysql.ini 
    - /etc/php/7.0/cli/conf.d/20-phar.ini 
    - /etc/php/7.0/cli/conf.d/20-posix.ini 
    - /etc/php/7.0/cli/conf.d/20-readline.ini 
    - /etc/php/7.0/cli/conf.d/20-shmop.ini 
    - /etc/php/7.0/cli/conf.d/20-sockets.ini 
    - /etc/php/7.0/cli/conf.d/20-sysvmsg.ini 
    - /etc/php/7.0/cli/conf.d/20-sysvsem.ini 
    - /etc/php/7.0/cli/conf.d/20-sysvshm.ini 
    - /etc/php/7.0/cli/conf.d/20-tokenizer.ini 
    You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode. 

Answer 1

请按照laravel文档5.1：https://laravel.com/docs/5.1#installation