从命令行，我发出：
composer install
Installing dependencies from lock file (including require-dev)
Verifying lock file contents can be installed on current platform.
Warning: The lock file is not up to date with the latest changes in composer.json. You may be getting outdated dependencies. It is recommended that you run `composer update` or `composer update <package name>`.
Your lock file does not contain a compatible set of packages. Please run composer update.
Problem 1
- doctrine/cache is locked to version v1.8.0 and an update of this package was not requested.
- doctrine/cache v1.8.0 requires php ~7.1 -> your php version (8.0.0) does not satisfy that requirement.
Problem 2
- doctrine/dbal is locked to version v2.9.2 and an update of this package was not requested.
- doctrine/dbal v2.9.2 requires php ^7.1 -> your php version (8.0.0) does not satisfy that requirement.
Problem 3
- doctrine/event-manager is locked to version v1.0.0 and an update of this package was not requested.
- doctrine/event-manager v1.0.0 requires php ^7.1 -> your php version (8.0.0) does not satisfy that
requirement.
Problem 4
- doctrine/inflector is locked to version v1.3.0 and an update of this package was not requested.
- doctrine/inflector v1.3.0 requires php ^7.1 -> your php version (8.0.0) does not satisfy that requirement.
Problem 5
- maatwebsite/excel is locked to version 3.1.13 and an update of this package was not requested.
- maatwebsite/excel 3.1.13 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 6
- markbaker/complex is locked to version 1.4.7 and an update of this package was not requested.
- markbaker/complex 1.4.7 requires php ^5.6.0|^7.0.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 7
- markbaker/matrix is locked to version 1.1.4 and an update of this package was not requested.
- markbaker/matrix 1.1.4 requires php ^5.6.0|^7.0.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 8
- opis/closure is locked to version 3.2.0 and an update of this package was not requested.
- opis/closure 3.2.0 requires php ^5.4 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 9
- phpoffice/phpspreadsheet is locked to version 1.6.0 and an update of this package was not requested.
- phpoffice/phpspreadsheet 1.6.0 requires ext-gd * -> it is missing from your system. Install or enable PHP's gd extension.
Problem 10
- ramsey/uuid is locked to version 3.8.0 and an update of this package was not requested.
- ramsey/uuid 3.8.0 requires php ^5.4 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 11
- renatomarinho/laravel-page-speed is locked to version 1.8.10 and an update of this package was not requested.
- renatomarinho/laravel-page-speed 1.8.10 requires php ^5.6 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 12
- symfony/psr-http-message-bridge is locked to version v1.2.0 and an update of this package was not
requested.
- symfony/psr-http-message-bridge v1.2.0 requires php ^7.1 -> your php version (8.0.0) does not satisfy that requirement.
Problem 13
- tijsverkoyen/css-to-inline-styles is locked to version 2.2.1 and an update of this package was not requested.
- tijsverkoyen/css-to-inline-styles 2.2.1 requires php ^5.5 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 14
- zendframework/zend-diactoros is locked to version 1.8.6 and an update of this package was not requested.
- zendframework/zend-diactoros 1.8.6 requires php ^5.6 || ^7.0 -> your php version (8.0.0) does not
satisfy that requirement.
Problem 15
- composer/semver is locked to version 1.5.0 and an update of this package was not requested.
- composer/semver 1.5.0 requires php ^5.3.2 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 16
- composer/xdebug-handler is locked to version 1.3.2 and an update of this package was not requested.
- composer/xdebug-handler 1.3.2 requires php ^5.3.2 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 17
- doctrine/annotations is locked to version v1.6.1 and an update of this package was not requested.
- doctrine/annotations v1.6.1 requires php ^7.1 -> your php version (8.0.0) does not satisfy that requirement.
Problem 18
- doctrine/instantiator is locked to version 1.2.0 and an update of this package was not requested.
- doctrine/instantiator 1.2.0 requires php ^7.1 -> your php version (8.0.0) does not satisfy that requirement.
Problem 19
- facebook/webdriver is locked to version 1.6.0 and an update of this package was not requested.
- facebook/webdriver 1.6.0 requires php ^5.6 || ~7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 20
- filp/whoops is locked to version 2.3.1 and an update of this package was not requested.
- filp/whoops 2.3.1 requires php ^5.5.9 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 21
- friendsofphp/php-cs-fixer is locked to version v2.15.0 and an update of this package was not requested.
- friendsofphp/php-cs-fixer v2.15.0 requires php ^5.6 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 22
- fzaninotto/faker is locked to version v1.8.0 and an update of this package was not requested.
- fzaninotto/faker v1.8.0 requires php ^5.3.3 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 23
- hamcrest/hamcrest-php is locked to version v2.0.0 and an update of this package was not requested. - hamcrest/hamcrest-php v2.0.0 requires php ^5.3|^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 24
- myclabs/deep-copy is locked to version 1.9.1 and an update of this package was not requested.
- myclabs/deep-copy 1.9.1 requires php ^7.1 -> your php version (8.0.0) does not satisfy that requirement.
Problem 25
- phar-io/manifest is locked to version 1.0.1 and an update of this package was not requested.
- phar-io/manifest 1.0.1 requires php ^5.6 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 26
- phar-io/version is locked to version 1.0.1 and an update of this package was not requested.
- phar-io/version 1.0.1 requires php ^5.6 || ^7.0 -> your php version (8.0.0) does not satisfy that
requirement.
Problem 27
- php-cs-fixer/diff is locked to version v1.3.0 and an update of this package was not requested.
- php-cs-fixer/diff v1.3.0 requires php ^5.6 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 28
- phpdocumentor/reflection-docblock is locked to version 4.3.1 and an update of this package was not requested.
- phpdocumentor/reflection-docblock 4.3.1 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 29
- phpdocumentor/type-resolver is locked to version 0.4.0 and an update of this package was not requested.
- phpdocumentor/type-resolver 0.4.0 requires php ^5.5 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 30
- phpspec/prophecy is locked to version 1.8.0 and an update of this package was not requested.
- phpspec/prophecy 1.8.0 requires php ^5.3|^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 31
- phpunit/php-code-coverage is locked to version 5.3.2 and an update of this package was not requested.
- phpunit/php-code-coverage 5.3.2 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 32
- phpunit/php-timer is locked to version 1.0.9 and an update of this package was not requested.
- phpunit/php-timer 1.0.9 requires php ^5.3.3 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 33
- phpunit/php-token-stream is locked to version 2.0.2 and an update of this package was not requested.
- phpunit/php-token-stream 2.0.2 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 34
- phpunit/phpunit is locked to version 6.5.14 and an update of this package was not requested.
- phpunit/phpunit 6.5.14 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 35
- phpunit/phpunit-mock-objects is locked to version 5.0.10 and an update of this package was not requested.
- phpunit/phpunit-mock-objects 5.0.10 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 36
- sebastian/code-unit-reverse-lookup is locked to version 1.0.1 and an update of this package was not requested.
- sebastian/code-unit-reverse-lookup 1.0.1 requires php ^5.6 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 37
- sebastian/comparator is locked to version 2.1.3 and an update of this package was not requested.
- sebastian/comparator 2.1.3 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 38
- sebastian/diff is locked to version 2.0.1 and an update of this package was not requested.
- sebastian/diff 2.0.1 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 39
- sebastian/environment is locked to version 3.1.0 and an update of this package was not requested.
- sebastian/environment 3.1.0 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 40
- sebastian/exporter is locked to version 3.1.0 and an update of this package was not requested.
- sebastian/exporter 3.1.0 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 41
- sebastian/global-state is locked to version 2.0.0 and an update of this package was not requested. - sebastian/global-state 2.0.0 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 42
- sebastian/object-enumerator is locked to version 3.0.3 and an update of this package was not requested.
- sebastian/object-enumerator 3.0.3 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 43
- sebastian/object-reflector is locked to version 1.1.1 and an update of this package was not requested.
- sebastian/object-reflector 1.1.1 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 44
- sebastian/recursion-context is locked to version 3.0.0 and an update of this package was not requested.
- sebastian/recursion-context 3.0.0 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 45
- theseer/tokenizer is locked to version 1.1.2 and an update of this package was not requested.
- theseer/tokenizer 1.1.2 requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
Problem 46
- webmozart/assert is locked to version 1.4.0 and an update of this package was not requested.
- webmozart/assert 1.4.0 requires php ^5.3.3 || ^7.0 -> your php version (8.0.0) does not satisfy th Problem 47
- doctrine/inflector v1.3.0 requires php ^7.1 -> your php version (8.0.0) does not satisfy that requirement.
- laravel/framework v5.5.45 requires doctrine/inflector ~1.1 -> satisfiable by doctrine/inflector[v1.3.0].
- laravel/framework is locked to version v5.5.45 and an update of this package was not requested.
To enable extensions, verify that they are enabled in your .ini files:
- C:\xampp\php\php.ini
You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
composer update
Loading composer repositories with package information
Updating dependencies
Your requirements could not be resolved to an installable set of packages.
Problem 1
- maatwebsite/excel 3.1.26 requires phpoffice/phpspreadsheet ^1.15 -> satisfiable by phpoffice/phpspreadsheet[1.15.0, 1.16.0].
- maatwebsite/excel[3.1.0, ..., 3.1.25] require php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.
- phpoffice/phpspreadsheet[1.15.0, ..., 1.16.0] require ext-gd * -> it is missing from your system.
Install or enable PHP's gd extension.
- Root composer.json requires maatwebsite/excel ^3.1 -> satisfiable by maatwebsite/excel[3.1.0, ..., 3.1.26].
To enable extensions, verify that they are enabled in your .ini files:
- C:\xampp\php\php.ini
You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.
我该如何解决这个问题？
我使用了这个命令行，突然事情就像魔法一样发生了！
composer update --ignore-platform-reqs
注意：这并不总是可接受的解决方案！
检查下面@Kamafeather的回答。
我遇到了类似的问题，发出了类似的消息：
Problem 1
- laminas/laminas-i18n[2.11.0, ..., 2.11.3] require php ^7.3 || ~8.0.0 -> your php version (8.1.10) does not satisfy that requirement.
- laminas/laminas-i18n[2.12.0, ..., 2.18.0] require ext-intl * -> it is missing from your system. Install or enable PHP's intl extension.
- laminas/laminas-mvc-form 2.0.0 requires laminas/laminas-i18n ^2.11.2 -> satisfiable by laminas/laminas-i18n[2.11.2, ..., 2.18.0].
- Root composer.json requires laminas/laminas-mvc-form ^2.0.0 -> satisfiable by laminas/laminas-mvc-form[2.0.0].
To enable extensions, verify that they are enabled in your .ini files:
- C:\php\php-8.1.10-nts-Win32-vs16-x64\php.ini
我在这里所做的是，我打开了位于错误消息中路径指向的文件夹中的 php 配置文件 (php.ini)（在您的情况下为 C:\xampp\php\php.ini），检查命名是否为扩展已被注释（前面有 ;）。
我将需要的注释掉，然后检查扩展目录是否在正确的文件夹中查找扩展（大多数情况下应该是extension_dir =“ext”）。就我而言，这是注释的，因此程序并不真正知道从哪里加载扩展。取消注释该行解决了我的问题。
当您第一次尝试时，请使用 --ignore-platform-reqs。 出现此错误是由于您的 php 版本不匹配问题。那么请使用
composer install --ignore-platform-reqs
编码快乐！
解决方案是，转到 PHP 的根文件夹（可能在 C:\Program Files\php 或 xampp\php 中）并搜索 php.ini 文件。在该文件中，找到注释行“;extension=fileinfo”并删除“;”所以它会被取消注释并保存文件。 这对我来说就是问题。 真的很愚蠢，但显然没有人默认修复它。
您可以忽略平台要求，使用：
composer update --ignore-platform-reqs
这是可以接受的，只是因为在这种特定情况下作曲家依赖项的要求显然太严格了。
考虑一下：
在 SemVer 中，插入符号 (^) 允许进行不更改版本字符串中最左边的非零数字的更新。对于 ^7.x.x，这意味着它将匹配从 7.0.0 到（但不包括）8.0.0 的任何版本。
因此，编写 PHP 版本要求时没有考虑未来的 PHP 版本（尽管它们可能仍然兼容）。
这是库作者的疏忽，因此跳过平台要求以弥补该问题是可以接受的！
任何其他情况可能需要：
修复
composer.jsoncomposer.jsoncaret更改为 greater-than 就足够了，使用
"php": ">=7"。