Composer install 实际上并没有安装库
Composer install doesn't actually install library
问题
这很奇怪。我只是将其添加到我的 composer.json 文件中：
"maatwebsite/excel": "~2.1.0"
然而，当我 运行 composer install 时，那个库没有安装：
composer show | grep excel
returns 没什么。
因此每次我 运行 我的部署脚本都会收到此错误：
> php artisan clear-compiled
PHP Fatal error: Uncaught Symfony\Component\Debug\Exception\FatalThrowableError: Class 'PHPExcel_Shared_Font' not found in /Users/Shared/dev/php/toters-api/config/excel.php:182
Stack trace:
#0 /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/LoadConfiguration.php(60): require()
#1 /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/LoadConfiguration.php(38): Illuminate\Foundation\Bootstrap\LoadConfiguration->loadConfigurationFiles(Object(Illuminate\Foundation\Application), Object(Illuminate\Config\Repository))
#2 /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(203): Illuminate\Foundation\Bootstrap\LoadConfiguration->bootstrap(Object(Illuminate\Foundation\Application))
#3 /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(267): Illuminate\Foundation\Application->bootstrapWith(Array)
#4 /Users/Shared/dev/php/toters-api/vendor/laravel/framew in /Users/Shared/dev/php/toters-api/config/excel.php on line 182
Fatal error: Uncaught Symfony\Component\Debug\Exception\FatalThrowableError: Class 'PHPExcel_Shared_Font' not found in /Users/Shared/dev/php/toters-api/config/excel.php on line 182
Symfony\Component\Debug\Exception\FatalThrowableError: Class 'PHPExcel_Shared_Font' not found in /Users/Shared/dev/php/toters-api/config/excel.php on line 182
这是预期的错误，因为 Composer 忽略了我的 maatwebsite/excel 库！
解决方法
我使用这些步骤来暴力破解它：
rm -rf vendor
rm composer.lock
composer install --no-scripts
但这显然是一个丑陋且昂贵的 hack（我已将其添加为 envoyer 自动部署中的预挂钩），并且它每次都有效，但它增加了自动部署的时间-部署过程。
参考资料
- 我的composer.json文件
- 我的composer.lock文件
问题
我如何 运行 Composer 命令强制它工作（但我还必须避免使用 composer update 命令，因为我不想在每次部署期间更新我的所有库，因为这会导致我的代码库发生不可预测的更新）
更新
我刚刚注意到 this library 在我们的版本上支持旧版本的 PHP - 这可能与它有关吗？
更新 2
运行 composer require maatwebsite/excel returns 如下：
composer require maatwebsite/excel
Using version ^3.0 for maatwebsite/excel
./composer.json has been updated
> php artisan clear-compiled
The compiled class file has been removed.
> php artisan ide-helper:generate
A new helper file was written to _ide_helper.php
Unexpected no document on Illuminate\Database\Eloquent\Model
Wrote expected docblock to /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php
> php artisan ide-helper:models -N
Model information was written to _ide_helper_models.php
> php artisan optimize
Generating optimized class loader
The compiled class file has been removed.
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Conclusion: remove laravel/framework v5.3.31
- Conclusion: don't install laravel/framework v5.3.31
- maatwebsite/excel 3.0.1 requires illuminate/support ^5.5 -> satisfiable by illuminate/support[v5.5.0, v5.5.16, v5.5.17, v5.5.2, v5.5.28, v5.5.33, v5.5.34, v5.5.35, v5.5.36, v5.5.37, v5.5.39, v5.5.40, v5.6.0, v5.6.1, v5.6.10, v5.6.11, v5.6.12, v5.6.13, v5.6.14, v5.6.15, v5.6.2, v5.6.3, v5.6.4, v5.6.5, v5.6.6, v5.6.7, v5.6.8, v5.6.9].
- maatwebsite/excel 3.0.0 requires illuminate/support ^5.6 -> satisfiable by illuminate/support[v5.6.0, v5.6.1, v5.6.10, v5.6.11, v5.6.12, v5.6.13, v5.6.14, v5.6.15, v5.6.2, v5.6.3, v5.6.4, v5.6.5, v5.6.6, v5.6.7, v5.6.8, v5.6.9].
- don't install illuminate/support v5.5.0|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.16|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.17|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.2|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.28|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.33|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.34|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.35|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.36|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.37|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.39|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.40|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.0|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.1|don't install laravel/framework v5.3.31
- illuminate/support v5.6.10 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.11 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.12 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.13 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.14 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.15 conflicts with laravel/framework[v5.3.31].
- don't install illuminate/support v5.6.2|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.3|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.4|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.5|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.6|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.7|don't install laravel/framework v5.3.31
- illuminate/support v5.6.8 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.9 conflicts with laravel/framework[v5.3.31].
- Installation request for laravel/framework (locked at v5.3.31, required as 5.3.*) -> satisfiable by laravel/framework[v5.3.31].
- Installation request for maatwebsite/excel ^3.0 -> satisfiable by maatwebsite/excel[3.0.0, 3.0.1].
Installation failed, reverting ./composer.json to its original content.
这是预期的，因为最新版本的 maatwebsite/excel 需要 laravel 5.5+,
但是当我运行composer require maatwebsite/excel:2.1的时候，还是报错：
./composer.json has been updated
> php artisan clear-compiled
The compiled class file has been removed.
> php artisan ide-helper:generate
A new helper file was written to _ide_helper.php
Tag Exists: @mixin \Eloquent in Illuminate\Database\Eloquent\Model
Tag Exists: @mixin \Illuminate\Database\Eloquent\Builder in Illuminate\Database\Eloquent\Model
Tag Exists: @mixin \Illuminate\Database\Query\Builder in Illuminate\Database\Eloquent\Model
> php artisan ide-helper:models -N
Model information was written to _ide_helper_models.php
> php artisan optimize
Generating optimized class loader
The compiled class file has been removed.
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for maatwebsite/excel 2.1 -> satisfiable by maatwebsite/excel[v2.1.0].
- Conclusion: remove laravel/framework v5.3.31
- Conclusion: don't install laravel/framework v5.3.31
- maatwebsite/excel v2.1.0 requires illuminate/filesystem 5.0.*|5.1.*|5.2.* -> satisfiable by illuminate/filesystem[v5.0.0, v5.0.22, v5.0.25, v5.0.26, v5.0.28, v5.0.33, v5.0.4, v5.1.1, v5.1.13, v5.1.16, v5.1.2, v5.1.20, v5.1.22, v5.1.25, v5.1.28, v5.1.30, v5.1.31, v5.1.41, v5.1.6, v5.1.8, v5.2.0, v5.2.19, v5.2.21, v5.2.24, v5.2.25, v5.2.26, v5.2.27, v5.2.28, v5.2.31, v5.2.32, v5.2.37, v5.2.43, v5.2.45, v5.2.6, v5.2.7].
- don't install illuminate/filesystem v5.0.0|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.22|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.25|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.26|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.28|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.33|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.4|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.1|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.13|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.16|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.2|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.20|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.22|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.25|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.28|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.30|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.31|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.41|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.6|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.8|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.0|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.19|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.21|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.24|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.25|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.26|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.27|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.28|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.31|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.32|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.37|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.43|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.45|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.6|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.7|don't install laravel/framework v5.3.31
- Installation request for laravel/framework (locked at v5.3.31, required as 5.3.*) -> satisfiable by laravel/framework[v5.3.31].
Installation failed, reverting ./composer.json to its original content.
这很奇怪，因为它应该支持 Laravel 5.3（我的 Laravel）：
但是我的 PHP 版本是 7.1。
在你的情况下，你可以尝试 composer require and that package name 即
composer require maatwebsite/excel
composer install 不像 npm install。我很确定如果你像你那样手动添加一个包，它会被忽略，因为 composer.lock 已经存在了。
- 做
composer update 会奏效。
- 或通过
composer require maatwebsite/excel 添加包
- 或删除
composer.lock 然后 运行 composer install
编辑：
composer require maatwebsite/excel 将尝试安装该软件包的最新版本，但因为您使用的是 laraval v5.3.31，所以您应该安装 maatwebsite/excel ~2.1.0。版本 3 适用于 laraval ^5.5
composer require "maatwebsite/excel:~2.1.0"
never never never never ever delete composer.lock - 除非你真的明白这意味着什么并且愿意承担后果。
您只需调用即可安装：
composer require maatwebsite/excel:~2.1
然后安装版本 2.1.27。
关于您的 "error" 消息的几句话。那里说 maatwebsite/excel v2.1.0 需要 illuminate/filesystem 5.0.*|5.1.*|5.2.*。这个包在同一个版本中被laravel取代了（你可以在composer.lock中"read"这个）。
但是您使用的是 laravel 5.3.31 因此存在版本冲突。但是 maatwebsite/excel 的更新版本与更多版本的 illuminate/*.
兼容
问题
这很奇怪。我只是将其添加到我的 composer.json 文件中：
"maatwebsite/excel": "~2.1.0"
然而，当我 运行 composer install 时，那个库没有安装：
composer show | grep excel
returns 没什么。
因此每次我 运行 我的部署脚本都会收到此错误：
> php artisan clear-compiled
PHP Fatal error: Uncaught Symfony\Component\Debug\Exception\FatalThrowableError: Class 'PHPExcel_Shared_Font' not found in /Users/Shared/dev/php/toters-api/config/excel.php:182
Stack trace:
#0 /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/LoadConfiguration.php(60): require()
#1 /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/LoadConfiguration.php(38): Illuminate\Foundation\Bootstrap\LoadConfiguration->loadConfigurationFiles(Object(Illuminate\Foundation\Application), Object(Illuminate\Config\Repository))
#2 /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(203): Illuminate\Foundation\Bootstrap\LoadConfiguration->bootstrap(Object(Illuminate\Foundation\Application))
#3 /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(267): Illuminate\Foundation\Application->bootstrapWith(Array)
#4 /Users/Shared/dev/php/toters-api/vendor/laravel/framew in /Users/Shared/dev/php/toters-api/config/excel.php on line 182
Fatal error: Uncaught Symfony\Component\Debug\Exception\FatalThrowableError: Class 'PHPExcel_Shared_Font' not found in /Users/Shared/dev/php/toters-api/config/excel.php on line 182
Symfony\Component\Debug\Exception\FatalThrowableError: Class 'PHPExcel_Shared_Font' not found in /Users/Shared/dev/php/toters-api/config/excel.php on line 182
这是预期的错误，因为 Composer 忽略了我的 maatwebsite/excel 库！
解决方法
我使用这些步骤来暴力破解它：
rm -rf vendor
rm composer.lock
composer install --no-scripts
但这显然是一个丑陋且昂贵的 hack（我已将其添加为 envoyer 自动部署中的预挂钩），并且它每次都有效，但它增加了自动部署的时间-部署过程。
参考资料
- 我的composer.json文件
- 我的composer.lock文件
问题
我如何 运行 Composer 命令强制它工作（但我还必须避免使用 composer update 命令，因为我不想在每次部署期间更新我的所有库，因为这会导致我的代码库发生不可预测的更新）
更新
我刚刚注意到 this library 在我们的版本上支持旧版本的 PHP - 这可能与它有关吗？
更新 2
运行 composer require maatwebsite/excel returns 如下：
composer require maatwebsite/excel
Using version ^3.0 for maatwebsite/excel
./composer.json has been updated
> php artisan clear-compiled
The compiled class file has been removed.
> php artisan ide-helper:generate
A new helper file was written to _ide_helper.php
Unexpected no document on Illuminate\Database\Eloquent\Model
Wrote expected docblock to /Users/Shared/dev/php/toters-api/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php
> php artisan ide-helper:models -N
Model information was written to _ide_helper_models.php
> php artisan optimize
Generating optimized class loader
The compiled class file has been removed.
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Conclusion: remove laravel/framework v5.3.31
- Conclusion: don't install laravel/framework v5.3.31
- maatwebsite/excel 3.0.1 requires illuminate/support ^5.5 -> satisfiable by illuminate/support[v5.5.0, v5.5.16, v5.5.17, v5.5.2, v5.5.28, v5.5.33, v5.5.34, v5.5.35, v5.5.36, v5.5.37, v5.5.39, v5.5.40, v5.6.0, v5.6.1, v5.6.10, v5.6.11, v5.6.12, v5.6.13, v5.6.14, v5.6.15, v5.6.2, v5.6.3, v5.6.4, v5.6.5, v5.6.6, v5.6.7, v5.6.8, v5.6.9].
- maatwebsite/excel 3.0.0 requires illuminate/support ^5.6 -> satisfiable by illuminate/support[v5.6.0, v5.6.1, v5.6.10, v5.6.11, v5.6.12, v5.6.13, v5.6.14, v5.6.15, v5.6.2, v5.6.3, v5.6.4, v5.6.5, v5.6.6, v5.6.7, v5.6.8, v5.6.9].
- don't install illuminate/support v5.5.0|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.16|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.17|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.2|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.28|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.33|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.34|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.35|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.36|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.37|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.39|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.5.40|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.0|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.1|don't install laravel/framework v5.3.31
- illuminate/support v5.6.10 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.11 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.12 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.13 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.14 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.15 conflicts with laravel/framework[v5.3.31].
- don't install illuminate/support v5.6.2|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.3|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.4|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.5|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.6|don't install laravel/framework v5.3.31
- don't install illuminate/support v5.6.7|don't install laravel/framework v5.3.31
- illuminate/support v5.6.8 conflicts with laravel/framework[v5.3.31].
- illuminate/support v5.6.9 conflicts with laravel/framework[v5.3.31].
- Installation request for laravel/framework (locked at v5.3.31, required as 5.3.*) -> satisfiable by laravel/framework[v5.3.31].
- Installation request for maatwebsite/excel ^3.0 -> satisfiable by maatwebsite/excel[3.0.0, 3.0.1].
Installation failed, reverting ./composer.json to its original content.
这是预期的，因为最新版本的 maatwebsite/excel 需要 laravel 5.5+,
但是当我运行composer require maatwebsite/excel:2.1的时候，还是报错：
./composer.json has been updated
> php artisan clear-compiled
The compiled class file has been removed.
> php artisan ide-helper:generate
A new helper file was written to _ide_helper.php
Tag Exists: @mixin \Eloquent in Illuminate\Database\Eloquent\Model
Tag Exists: @mixin \Illuminate\Database\Eloquent\Builder in Illuminate\Database\Eloquent\Model
Tag Exists: @mixin \Illuminate\Database\Query\Builder in Illuminate\Database\Eloquent\Model
> php artisan ide-helper:models -N
Model information was written to _ide_helper_models.php
> php artisan optimize
Generating optimized class loader
The compiled class file has been removed.
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for maatwebsite/excel 2.1 -> satisfiable by maatwebsite/excel[v2.1.0].
- Conclusion: remove laravel/framework v5.3.31
- Conclusion: don't install laravel/framework v5.3.31
- maatwebsite/excel v2.1.0 requires illuminate/filesystem 5.0.*|5.1.*|5.2.* -> satisfiable by illuminate/filesystem[v5.0.0, v5.0.22, v5.0.25, v5.0.26, v5.0.28, v5.0.33, v5.0.4, v5.1.1, v5.1.13, v5.1.16, v5.1.2, v5.1.20, v5.1.22, v5.1.25, v5.1.28, v5.1.30, v5.1.31, v5.1.41, v5.1.6, v5.1.8, v5.2.0, v5.2.19, v5.2.21, v5.2.24, v5.2.25, v5.2.26, v5.2.27, v5.2.28, v5.2.31, v5.2.32, v5.2.37, v5.2.43, v5.2.45, v5.2.6, v5.2.7].
- don't install illuminate/filesystem v5.0.0|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.22|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.25|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.26|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.28|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.33|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.0.4|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.1|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.13|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.16|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.2|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.20|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.22|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.25|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.28|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.30|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.31|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.41|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.6|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.1.8|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.0|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.19|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.21|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.24|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.25|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.26|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.27|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.28|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.31|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.32|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.37|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.43|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.45|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.6|don't install laravel/framework v5.3.31
- don't install illuminate/filesystem v5.2.7|don't install laravel/framework v5.3.31
- Installation request for laravel/framework (locked at v5.3.31, required as 5.3.*) -> satisfiable by laravel/framework[v5.3.31].
Installation failed, reverting ./composer.json to its original content.
这很奇怪，因为它应该支持 Laravel 5.3（我的 Laravel）：
但是我的 PHP 版本是 7.1。
在你的情况下，你可以尝试 composer require and that package name 即
composer require maatwebsite/excel
composer install 不像 npm install。我很确定如果你像你那样手动添加一个包，它会被忽略，因为 composer.lock 已经存在了。
- 做
composer update会奏效。 - 或通过
composer require maatwebsite/excel 添加包
- 或删除
composer.lock然后 运行composer install
编辑：
composer require maatwebsite/excel 将尝试安装该软件包的最新版本，但因为您使用的是 laraval v5.3.31，所以您应该安装 maatwebsite/excel ~2.1.0。版本 3 适用于 laraval ^5.5
composer require "maatwebsite/excel:~2.1.0"
never never never never ever delete composer.lock - 除非你真的明白这意味着什么并且愿意承担后果。
您只需调用即可安装：
composer require maatwebsite/excel:~2.1
然后安装版本 2.1.27。
关于您的 "error" 消息的几句话。那里说 maatwebsite/excel v2.1.0 需要 illuminate/filesystem 5.0.*|5.1.*|5.2.*。这个包在同一个版本中被laravel取代了（你可以在composer.lock中"read"这个）。
但是您使用的是 laravel 5.3.31 因此存在版本冲突。但是 maatwebsite/excel 的更新版本与更多版本的 illuminate/*.