composer安装和使用

1. 下载composer:  https://docs.phpcomposer.com/00-intro.html#Installation-Windows                                                                                                                              双击进行安装                                                                                                                                                                                                                                                                                     然后不用填写，直接下一步                                                        
2. 检验安装composer是否成功安装                                                                                                                                           以管理员身份运行cmd                                                                                                                                                           出现以下界面，就表示我们已经安装好composer工具了:                                                                   或者在phpstudy中进行检测 ，其他选项菜单-其他高级应用-PHP Composer，点开：          

3.    Composer测试使用：                                                                                                                                                         在项目文件夹下创建composer.json文件，添加需要下载的组件：                                                                                          在cmd中，进入改文件夹，执行composer install命令：                                                                  可以看到,他自动生成了一个vendor文件夹,组件全下载在了vendor下面：                                                                                        组件使用：在文件中引入vendor下的autoload.php文件,这是官方的自动加载文件， new对象,调用方法即可：                  require 'vendor/autoload.php';                                     $image=new \topthink\Image ();                                       $test=$image->options();

4. 问题1：                                                                                                                                                                                  安装过程中报错，Unable to load dynamic library 'E:\phpStudy\php\php-5.5.38\ext\php_igbinary.dll'                                    解决办法：添加php_igbinary.dll扩展                                                                                                                                      下载完对应版本放入php/ext/下，在php.ini中添加扩展，重启。                                                                                            下载地址：https://blog.csdn.net/cmj8043719242/article/details/92835392

5. 问题2：                                                                                                                                                                                  报错无效的dynwrap.dll扩展，解决办法：在php.ini中注释掉 ;extension=dynwrap.dll

6. 问题3：                                                                                                                                                                                  在下载组件的时候会非常慢,这需要修改composer的配置文件:                                                                                              在cmd中输入  composer config -l -g    命令,得到composer配置文件的路径                                                                                          可进入路径下的config.json,修改下载路径