本文比較了Laravel 8和9，強調(diào)了影響升級決策的主要差異。 Laravel 9需要PHP 8.1，更新的Symfony組件，并提供性能改進和新功能。 Laravel 8升級涉及P

Laravel 8和Laravel 9以及何時使用的關(guān)鍵區(qū)別是什么？

Laravel 9于2022年2月發(fā)行，建立在2020年9月發(fā)行的Laravel 8上。雖然跳躍似乎是漸進的，但存在幾種關(guān)鍵區(qū)別，影響了它們之間的選擇。最重要的變化圍繞更新的依賴性，改善性能和新功能。

關(guān)鍵差異：

• PHP Version: Laravel 9 requires PHP 8.1, a significant jump from Laravel 8's PHP 8.0 requirement.這需要在升級之前檢查現(xiàn)有代碼庫的兼容性和依賴性與php 8.1的兼容性。 PHP 8.1介紹了幾種性能增強和新功能，例如枚舉和一流的可呼叫語法，這些語法是Laravel 9的利用。
• Improved Symfony Components: Laravel 9 upgrades many of its underlying Symfony components to their latest versions.這帶來了性能改進和安全補丁，但也有可能引入需要調(diào)整代碼的破壞變化。
• New Features (discussed in more detail below): While not a complete overhaul, Laravel 9 incorporates new features, such as improved query builder functionality and enhancements to the testing framework.

何時使用每個：

• Laravel 8: If your project is already running smoothly on Laravel 8, and you're not experiencing performance bottlenecks or needing the specific features of Laravel 9, sticking with Laravel 8 might be the best approach.升級引入了潛在的風(fēng)險（稍后討論）。僅當(dāng)您需要新的Symfony組件或PHP 8.1的特定功能時，請考慮升級。
• Laravel 9: If you're starting a new project, Laravel 9 is the recommended choice.在利用最新PHP版本的同時，它受益于性能改進和新功能。如果您需要提高性能，新功能會大大改善工作流程，或者您正在積極維護和開發(fā)應(yīng)用程序，則建議現(xiàn)有項目升級到Laravel 9。

與Laravel 8相比，Laravel 9中最重要的性能改善是什么？

Laravel 9具有多種性能增強功能，主要源于更新的Symfony組件和PHP 8.1的使用。雖然在大多數(shù)情況下并不明顯地震驚地球，但累積效應(yīng)可能很明顯，尤其是在較大的應(yīng)用中。

• Symfony Component Upgrades: The updated Symfony components, such as the upgraded Symfony\Component\HttpFoundation and Symfony\Component\Routing , often include internal optimizations that improve request handling and routing efficiency.這些通常是在罩上的改進下，在代碼本身中不容易可見，但可以通過基準(zhǔn)測試來證明。
• PHP 8.1 Enhancements: PHP 8.1 itself offers performance improvements, including enhanced JIT compilation and optimizations in various areas. Laravel 9利用這些改進。在某些情況下，諸如Enums之類的功能雖然在實施中與實現(xiàn)無直接相關(guān)，但可以導(dǎo)致更清潔，更有效的代碼。
• Improved Query Builder (subtle): While not a massive performance overhaul, the Laravel 9 query builder might offer marginal performance gains in specific use cases due to internal optimizations and better handling of certain query types.

至關(guān)重要的是要了解性能增長是漸進的，并在很大程度上取決于應(yīng)用程序的復(fù)雜性和使用模式。升級前后對您的特定應(yīng)用程序進行基準(zhǔn)測試對于準(zhǔn)確評估性能改進至關(guān)重要。

我應(yīng)該將Laravel 8項目升級到Laravel 9，涉及哪些潛在風(fēng)險？

從Laravel 8升級到Laravel 9是需要仔細考慮的決定。盡管有好處，但潛在風(fēng)險需要采取精心計劃的方法。

升級的原因：

• Performance Improvements: As discussed earlier, performance gains are possible, though their magnitude varies.
• New Features: Access to Laravel 9's new features might significantly improve your development workflow or add crucial functionality.
• Security Patches: Upgrading ensures access to the latest security patches provided by both Laravel and its underlying components.

潛在風(fēng)險：

• Breaking Changes: The updated Symfony components and the PHP 8.1 requirement might introduce breaking changes.這意味著您現(xiàn)有的代碼可能需要進行重大修改才能與Laravel 9正確運行。
• Dependency Conflicts: Your existing third-party packages might not be compatible with Laravel 9 or PHP 8.1, requiring you to find updated versions or alternatives.
• Testing Overhead: Thorough testing is crucial after upgrading to ensure everything functions as expected.這涉及大量時間投資。
• Downtime: The upgrade process itself might require downtime, depending on your deployment strategy.

Recommendation: Before upgrading, thoroughly assess the potential benefits against the risks.創(chuàng)建一個測試環(huán)境來模擬升級過程并確定任何破壞變化或依賴性問題。通常建議采用逐步的，分階段的升級方法，也許是從應(yīng)用程序中較小，不太關(guān)鍵的部分開始的。

Laravel 9中的哪些新功能可能會顯著影響我現(xiàn)有的Laravel 8應(yīng)用程序的功能？

盡管Laravel 9沒有引入根本范式變化，但一些新功能可能會影響您現(xiàn)有的Laravel 8應(yīng)用程序的功能：

• PHP 8.1 Features: The use of PHP 8.1 features like enums might necessitate code changes if your application relies on similar functionality implemented differently.
• Improved Query Builder: While generally not breaking, changes to the query builder's behavior could require adjustments to your database interaction code, especially if you're using less common query methods.
• New or Updated Package Compatibility: Many packages have updated their code to take advantage of Laravel 9's features.這可能會引入其功能變化，并需要在代碼庫中進行更新。檢查包裝維護者提供的升級說明。
• Symfony Component Changes: Changes within the underlying Symfony components, even if subtle, might impact your application's behavior.仔細測試對于識別和解決任何意外后果至關(guān)重要。

在進行升級之前，請咨詢Laravel 9官方升級指南，并仔細檢查Laravel及其依賴項的Changelog至關(guān)重要。這將幫助您預(yù)期并減輕對應(yīng)用程序功能的潛在影響。

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