> For the complete documentation index, see [llms.txt](https://ethan-lin.gitbook.io/refactoring/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ethan-lin.gitbook.io/refactoring/dan-wei-zhuan-huan/index.md).

# 项目导学

## 项目介绍

这个练习是对一道已有实现的“单位转换”题进行重构。题目本身并不算复杂，但我们却从中看到混乱的先兆：混乱的命名、嵌套铺展的`if-else`、可读性较差……通过这个项目，学员可以对重构的核心原理有所了解，并能通过练习掌握小步前进、频繁测试的重构习惯，为后续的重构学习打好基础。

## 教学目标

1. 使学员养成频繁运行测试的习惯
2. 掌握重构基本原理，具备拆分步骤、小步前进的重构能力
3. 在掌握原理的基础上掌握两项最常用的重构手法：方法重命名、提炼方法

## 项目学习时长

5 小时。

* 任务 1：30 min
* 任务 2：30 min
* 任务 3：30 min
* 任务 4：1 h
* 任务 5：1 h
* 任务 6：30 min
* 任务 7：1 h

## 能力目标

* 掌握使用工具运行单元测试的方法
* 理解重构基本原理：十六字心法
* 掌握“函数重命名”重构手法
* 掌握“提炼函数”重构手法
* 熟悉基本的重构快捷键

## 技能目标

* 能使用 IDE 或控制台运行测试
* 能设计或理解重构手法的步骤分解
* 能在 10 秒内完成一次重构操作
* 能使用快捷键加快重构过程


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