> For the complete documentation index, see [llms.txt](https://qcrao91.gitbook.io/go/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://qcrao91.gitbook.io/go/fan-she/shi-mo-shi-fan-she.md).

# 什么是反射

维基百科上反射的定义：

> 在计算机科学中，反射是指计算机程序在运行时（Run time）可以访问、检测和修改它本身状态或行为的一种能力。用比喻来说，反射就是程序在运行的时候能够“观察”并且修改自己的行为。

难道不用反射就不能在运行时访问、检测和修改它本身的状态和行为吗？

问题的回答，其实要首先理解什么叫访问、检测和修改它本身状态或行为，它的本质是什么？

实际上，它的本质是程序在运行期探知对象的类型信息和内存结构。不用反射能行吗？可以的！使用汇编语言，直接和内层打交道，可以获取任何信息？但是，当编程迁移到高级语言上来之后，就不行了！只能通过`反射`来达到此项技能。

不同语言的反射模型不尽相同，有些语言还不支持反射。《Go 语言圣经》中是这样定义反射的：

> Go 语言提供了一种机制在运行时更新变量和检查它们的值、调用它们的方法，但是在编译时并不知道这些变量的具体类型，这称为反射机制。


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