下载composer.phar文件

$ curl -sS https://getcomposer.org/installer | php

将composer.phar移动到环境变量中并且更名为composer

$ mv ./composer.phar  /usr/local/bin/composer

使用国内其他镜像

$ composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/ (阿里)
$ composer config -g repo.packagist composer https://mirrors.huaweicloud.com/repository/php/ //华为云
$ composer config -g repo.packagist composer https://packagist.phpcomposer.com  //中国全量镜像 
$ composer config -g repo.packagist composer https://mirrors.cloud.tencent.com/composer/  //腾讯云 

$ composer config -g --unset repos.packagist  //取消全局配置

遇到安装问题尝试执行以下命令

$ composer self-update
$ composer diagnose
$ composer clear
$ composer update --lock
$ composer update --ignore-platform-reqs

    - Can only install one of: easyswoole/component[2.0.1, 1.9.2].
    - Can only install one of: easyswoole/component[2.0.2, 1.9.2].
    - Can only install one of: easyswoole/component[2.0.3, 1.9.2].
    - Can only install one of: easyswoole/component[2.0.4, 1.9.2].
//此时我们需要同步一下各自版本，建议使用命令：
$ composer update --ignore-platform-reqs

Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 6 installs, 4 updates, 5 removals
  - Removing symfony/polyfill-util (v1.18.0)
  - Removing symfony/polyfill-php56 (v1.18.0)
  - Removing nikic/php-parser (v4.6.0)
  - Removing jeremeamia/superclosure (2.4.0)
  - Removing easyswoole/validate (1.2.6)
  - Installing opis/closure (3.5.5): Downloading (100%)         
  - Updating easyswoole/component (1.9.2 => 2.2.1): Downloading (100%)         
  - Updating easyswoole/task (1.0.4 => 1.1.1): Downloading (100%)         
  - Installing easyswoole/socket (1.1.12): Downloading (100%)         
  - Updating easyswoole/http (1.3.3 => 1.7.12): Downloading (100%)         
  - Updating easyswoole/easyswoole (3.3.0 => 3.3.7): Downloading (100%)         
  - Installing easyswoole/pool (1.0.11): Downloading (100%)         
  - Installing easyswoole/ddl (1.0.7): Downloading (100%)         
  - Installing easyswoole/mysqli (2.2.6): Downloading (100%)         
  - Installing easyswoole/orm (1.4.16): Downloading (100%)         
Writing lock file
Generating autoload files

验证版本

$ composer -V

常用模块命令

$ composer update 
$ composer update laravel/framework  //更新laravel主框架

$ composer require predis/predis  //下载并安装redis模块
$ composer require overtrue/laravel-filesystem-qiniu //七牛上传
$ composer require overtrue/pinyin //拼音
$ composer require hhxsv5/laravel-s //swool 
$ composer require jaeger/querylist //php的jquery
$ composer require jaeger/querylist:4.1 //php的jquery  安装指定的版本 
$ composer require mews/captcha //图片验证码

//sftp模块
$ composer require league/flysystem:*   //*表示任何兼容的版本都可以
//如果安装失败,删除根目录下的composer.lock , 并执行:composer install
$ composer require league/flysystem-sftp:*


$ composer require intervention/image  //图片处理
//在 app/config/app.php 'providers' =>[...] 添加以下（容器服务注册）
Intervention\Image\ImageServiceProvider::class  
//在 app/config/app.php 'aliases' =>[...] 添加以下（门面注册:[可以直接使用Image::make()]）
'Image' => Intervention\Image\Facades\Image::class 
修改驱动为imagick （默认为GD驱动--可以不做配置）  
# php artisan vendor:publish --provider="Intervention\Image\ImageServiceProviderLaravelRecent" 
//这时你的config目录下会多出一个image.php
将 'driver' => 'gd' 改为  'driver' => 'imagick' 即可 

 
//安装：imagick 
yum install -y ImageMagick
yum install -y ImageMagick-devel
pecl install imagick
echo "extension=imagick.so" >> /etc/php.ini 


//其他模块
$ composer require smalot/pdfparser //pdf解释器
$ composer require yansongda/pay //阿里支付
$ composer require overtrue/laravel-wechat  //微信支付
$ composer require algolia/algoliasearch-client-php //手机短信模块  

//卸载
$ composer remove jaeger/querylist 


//更新缓存
$ composer update --lock  //更新lock文件
$ composer update nothing  //更新lock文件
$ composer clear-cache  //清理缓存
$ composer install
$ composer dump-autoload

$ php artisan cache:clear
$ php artisan config:clear 
$ php artisan route:clear 
$ php artisan route:cache