致命错误：Class＆＃39; Symfony \ Component \ HttpFoundation \ Request＆＃39;未找到

Question

我只是在终端中运行composer update命令，但我无法正确更新。当我输入我的项目URL时，有很多PHP错误。我纠正了所有这些，但这个仍然存在。我搜索了它，但无法找到任何解决方案。我遇到了这个错误：

有人有任何想法吗？

这是composer.json文件：

{
    "name": "laravel/laravel",
    "description": "The Laravel Framework.",
    "keywords": ["framework", "laravel"],
    "license": "MIT",
    "type": "project",
    "require": {
        "php": ">=5.6.4",
        "intervention/image": "^2.4",
        "laravel/framework": "5.4.*",
        "laravel/tinker": "~1.0",
        "maatwebsite/excel": "~2.1.0"
    },
    "require-dev": {
        "barryvdh/laravel-ide-helper": "^2.3",
        "fzaninotto/faker": "~1.4",
        "mockery/mockery": "0.9.*",
        "phpunit/phpunit": "~5.7"
    },
    "autoload": {
        "classmap": [
            "database"
        ],

        "psr-4": {
            "App\\": "app/"
        },
        "files" :[
            "app/Helper.php"
        ]
    },

    "autoload-dev": {
        "psr-4": {
            "Tests\\": "tests/"
        }
    },
    "scripts": {
        "post-root-package-install": [
            "php -r \"file_exists('.env') || copy('.env.example', '.env');\""
        ],
        "post-create-project-cmd": [
            "php artisan key:generate"
        ],
        "post-install-cmd": [
            "Illuminate\\Foundation\\ComposerScripts::postInstall",
            "php artisan optimize"
        ],
        "post-update-cmd": [
            "Illuminate\\Foundation\\ComposerScripts::postUpdate",
            "php artisan ide-helper:generate",
            "php artisan ide-helper:meta",
            "php artisan optimize"
        ]
    },
    "config": {
        "preferred-install": "dist",
        "sort-packages": true,
        "optimize-autoloader": true
    }


}