已经有很多很好的答案了，但让我看看我是否能给你另一个观点。

为了简化事情，您可以将框架视为一个除了实际功能之外完整的应用程序。你插入功能和PRESTO!你有一个应用程序。

Consider, say, a GUI framework. The framework contains everything you need to make an application. Indeed you can often trivially make a minimal application with very few lines of source that does absolutely nothing -- but it does give you window management, sub-window management, menus, button bars, etc. That's the framework side of things. By adding your application functionality and "plugging it in" to the right places in the framework you turn this empty app that does nothing more than window management, etc. into a real, full-blown application.

对于web应用程序，服务器端应用程序等也有类似类型的框架。在每种情况下，框架提供了大量乏味、重复的代码(希望如此)，而您提供了实际的问题域功能。(这是理想状态。当然，在现实中，框架的成功有很大的变数。)

我再次强调，这是对框架的简化观点。我没有使用像“控制反转”之类的可怕术语，尽管大多数框架都内置了这样可怕的概念。既然你是初学者，我想我就不给你行话了，用一个简单的比喻。

框架具有您可能需要的一些功能。您可能需要某种具有内置排序机制的数组。或者，您可能需要一个窗口，您想在其中放置一些控件，所有这些都可以在框架中找到。这是一种跨越你自己作品框架的作品。

编辑: 好吧，我将要挖掘你们试图告诉我的东西;)你可能没有注意到“跨越一个框架的工作……”这行之间的信息。 在它越陷越深之前。我试着给它一个地板，希望你优雅地: 我在这里找到了一个很好的解释“库和框架的区别”的问题 http://ifacethoughts.net/2007/06/04/difference-between-a-library-and-a-framework/

从技术上讲，您不需要框架。如果你想做一个非常非常简单的网站(想想1992年的网页)，你可以用硬编码的HTML和一些CSS来完成。

如果你想做一个现代的网络应用，你实际上也不需要使用框架。

You can instead choose to write all of the logic you need yourself, every time. You can write your own data-persistence/storage layer, or - if you're too busy - just write custom SQL for every single database access. You can write your own authentication and session handling layers. And your own template rending logic. And your own exception-handling logic. And your own security functions. And your own unit test framework to make sure it all works fine. And your own... [goes on for quite a long time]

然后，如果您确实使用了一个框架，您将能够从优秀的、通常是同行评审的、经过很好测试的其他开发人员的工作中受益，他们可能比您更好。您可以快速构建想要的内容，而不必花费时间构建或过于担心上面列出的基础设施项目。

您可以在更短的时间内完成更多的工作，并且知道您正在使用或扩展的框架代码很可能比您自己做得更好。

那么成本呢?花点时间学习框架。但是，正如几乎每个web开发人员都会证明的那样，花时间学习从使用你选择的任何框架中获得大量(真的，大量)好处是绝对值得的。

一个简单的解释是:框架是一个可以围绕它构建应用程序的支架。

A framework generally provides some base functionality which you can use and extend to make more complex applications from, there are frameworks for all sorts of things. Microsofts MVC framework is a good example of this. It provides everything you need to get off the ground building website using the MVC pattern, it handles web requests, routes and the like. All you have to do is implement "Controllers" and provide "Views" which are two constructs defined by the MVC framework. The MVC framework then handles calling your controllers and rendering your views.

也许不是最好的措辞，但我希望它有帮助

在最低的层次上，框架是一个环境，在其中您可以使用一组工具

这些工具以库、配置文件等形式出现。

这个所谓的“环境”为您提供了基本的设置(错误报告、日志文件、语言设置等)……它可以被修改，扩展和构建。

人们实际上不需要框架，这只是想要节省时间的问题，而其他人只是个人喜好的问题。

人们会证明有了框架，你就不必从头开始编码了。但这些只是人们混淆了库和框架。

我在这里没有偏见，实际上我现在使用的是一个框架。

维基百科(软件框架)的摘要(第一个谷歌点击顺便说一下)解释得很好:

A software framework, in computer programming, is an abstraction in which common code providing generic functionality can be selectively overridden or specialized by user code providing specific functionality. Frameworks are a special case of software libraries in that they are reusable abstractions of code wrapped in a well-defined Application programming interface (API), yet they contain some key distinguishing features that separate them from normal libraries. Software frameworks have these distinguishing features that separate them from libraries or normal user applications: inversion of control - In a framework, unlike in libraries or normal user applications, the overall program's flow of control is not dictated by the caller, but by the framework.[1] default behavior - A framework has a default behavior. This default behavior must actually be some useful behavior and not a series of no-ops. extensibility - A framework can be extended by the user usually by selective overriding or specialized by user code providing specific functionality. non-modifiable framework code - The framework code, in general, is not allowed to be modified. Users can extend the framework, but not modify its code.

您可能“需要”它，因为它在开发应用程序时为您提供了一个很好的快捷方式，因为它包含了许多已经编写和测试过的功能。原因与我们使用软件库的原因非常相似。