《重构-改善既有代码设计》是被众多程序员推荐的一本经典。但问题是其中的一些案例是js写的。作为一个c#开发人员，看起来不太习惯。所以特意抄袭了一版C#代码。
我想重构的一个重要的好处就是方便理解，易于修改。所以我就不说这段代码的功能是啥了。好的代码应该就是一眼就能看出是干啥的。如果一段代码理解起来非常困难，那就说明这段代码需要重构了。
不再废话，直接COPY代码（未重构的原始代码），之后会将重构的代码慢慢放出来。重现书中重构的手法以及效果。作为自己学习的记录。
剧目类
Play.cs
1 class Play
2 {
3 public string name;
4
5 public string type;
6 }
View Code
演出类
Performance.cs
1 class Performance
2 {
3 public string playID;
4
5 public int audience;
6 }
View Code
费用清单类
Invoice.cs
1 class Invoice
2 {
3 public string Customer;
4
5 public List<Performance> performances=new List<Performance>();
6 }
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马戏团类-----唉？好像应该是剧团才对啊,魂淡,算了就当是剧团吧
Circus.cs 在构造函数中的是演示数据
1 using System;
2 using System.Collections.Generic;
3 using System.Globalization;
4
5 namespace Refactoring
6 {
7 public class Circus
8 {
9 private readonly Dictionary<string, Play> _plays;
10
11 private readonly Invoice _invoice;
12
13 public Circus()
14 {
15 _invoice = new Invoice {Customer = "BigCo"};
16 _invoice.performances.Add(new performance {playID = "hamlet", audience = 55});
17 _invoice.performances.Add(new performance {playID = "as-like", audience = 35});
18 _invoice.performances.Add(new performance {playID = "othello", audience = 40});
19 _plays = new Dictionary<string, Play>();
20 _plays.Add("hamlet", new Play {name = "hamlet", type = "tragedy"});
21 _plays.Add("as-like", new Play {name = "As You Like It", type = "comedy"});
22 _plays.Add("othello", new Play {name = "Othello", type = "tragedy"});
23 }
24
25 public string Statement()
26 {
27 int totalAmount = 0;
28 int volumeCredits = 0;
29 string result = $"Statement for {_invoice.Customer} \n";
30 NumberFormatInfo nfi = new CultureInfo("en-US").NumberFormat;
31 nfi.CurrencyDecimalDigits = 2;
32
33 foreach (var perf in _invoice.performances)
34 {
35 Play play = _plays[perf.playID];
36 int thisAmount = 0;
37
38 switch (play.type)
39 {
40 case "tragedy":
41 thisAmount = 40000;
42 if (perf.audience > 30)
43 {
44 thisAmount += 1000 * (perf.audience - 30);
45 }
46
47 break;
48 case "comedy":
49 thisAmount = 30000;
50 if (perf.audience > 20)
51 {
52 thisAmount += 1000 + 500 * (perf.audience - 20);
53 }
54
55 break;
56 default:
57 throw new Exception($"unknown type:{play.type}");
58 }
59
60 //add volume credits
61 volumeCredits += Math.Max(perf.audience - 30, 0);
62 //add extra credit for every ten comedy attendees
63 if ("comedy" == play.type)
64 {
65 volumeCredits += perf.audience / 5;
66 }
67
68 //print line for this order
69 result += $"{play.name}: {string.Format(nfi, "{0:C}", thisAmount / 100)}({perf.audience}seats)\n";
70 totalAmount += thisAmount;
71 }
72
73 result += $"Amount owed is {string.Format(nfi, "{0:C}", totalAmount / 100)}\n";
74 result += $"You earned {volumeCredits} credits \n";
75 return result;
76 }
77 }
78 }
View Code
最后就是main函数啦
1 private static void Main(string[] args)
2 {
3 string result = new Circus().Statement();
4 Console.Write(result);
5 Console.Read();
6 }
View Code
执行结果
话说，像我这种不求上进的百度程序猿。一开始觉得这些代码没啥问题啊。甚至还觉得命名挺规范=.=
想要学好重构，就必须拥有一些程序猿的直觉，能够嗅出代码的坏味道。
首先这个Statement方法体太长了。。。如果整个项目都是这种代码，我敢保证最多看半个小时，就觉得累了。。。
所以这里就有 代码的坏味道之： 过长函数
初一看，这个switch分支处理代码就可以提取出来单独作为一个方法,这个技巧就是提炼函数.然后我们就给这个方法取一个方法名，取名自古就是一个讲究的活。最好能够根据名字就知道这个方法是要干什么的。如果项目里面的方法名都是methodA这样随意的话，那阅读这些代码太浪费时间和精力了。还没看两个方法就累了。。这还怎么玩。。。这就是另外一种代码的坏味道:神秘命名。说干就干
1 public string Statement()
2 {
3 int totalAmount = 0;
4 int volumeCredits = 0;
5 string result = $"Statement for {_invoice.Customer} \n";
6 NumberFormatInfo nfi = new CultureInfo("en-US").NumberFormat;
7 nfi.CurrencyDecimalDigits = 2;
8
9 foreach (var perf in _invoice.performances)
10 {
11 Play play = _plays[perf.playID];
12 int thisAmount = AmountFor(perf, play);
13
14 //add volume credits
15 volumeCredits += Math.Max(perf.audience - 30, 0);
16 //add extra credit for every ten comedy attendees
17 if ("comedy" == play.type)
18 {
19 volumeCredits += perf.audience / 5;
20 }
21
22 //print line for this order
23 result += $"{play.name}: {string.Format(nfi, "{0:C}", thisAmount / 100)}({perf.audience}seats)\n";
24 totalAmount += thisAmount;
25 }
26
27 result += $"Amount owed is {string.Format(nfi, "{0:C}", totalAmount / 100)}\n";
28 result += $"You earned {volumeCredits} credits \n";
29 return result;
30 }
31
32 private int AmountFor(Performance perf, Play play)
33 {
34 int thisAmount;
35 switch (play.type)
36 {
37 case "tragedy":
38 thisAmount = 40000;
39 if (perf.audience > 30)
40 {
41 thisAmount += 1000 * (perf.audience - 30);
42 }
43
44 break;
45 case "comedy":
46 thisAmount = 30000;
47 if (perf.audience > 20)
48 {
49 thisAmount += 1000 + 500 * (perf.audience - 20);
50 }
51
52 break;
53 default:
54 throw new Exception($"unknown type:{play.type}");
55 }
56
57 return thisAmount;
58 }
View Code
这还不够,对于AmountFor这个方法,还要做两处小的修改.perf这样的缩写对于理解没有任何帮助,所以要把它改回原名aPerformance（不要缩写也是代码美学之一）.在方法内部我也觉得thisAmount改为result这样更便于理解。如此一来代码就成了这样
1 public string Statement()
2 {
3 int totalAmount = 0;
4 int volumeCredits = 0;
5 string result = $"Statement for {_invoice.Customer} \n";
6 NumberFormatInfo nfi = new CultureInfo("en-US").NumberFormat;
7 nfi.CurrencyDecimalDigits = 2;
8
9 foreach (var perf in _invoice.performances)
10 {
11 Play play = _plays[perf.playID];
12 int thisAmount = AmountFor(perf, play);
13
14 //add volume credits
15 volumeCredits += Math.Max(perf.audience - 30, 0);
16 //add extra credit for every ten comedy attendees
17 if ("comedy" == play.type)
18 {
19 volumeCredits += perf.audience / 5;
20 }
21
22 //print line for this order
23 result += $"{play.name}: {string.Format(nfi, "{0:C}", thisAmount / 100)}({perf.audience}seats)\n";
24 totalAmount += thisAmount;
25 }
26
27 result += $"Amount owed is {string.Format(nfi, "{0:C}", totalAmount / 100)}\n";
28 result += $"You earned {volumeCredits} credits \n";
29 return result;
30 }
31
32 private int AmountFor(Performance aPerformance, Play play)
33 {
34 int result;
35 switch (play.type)
36 {
37 case "tragedy":
38 result = 40000;
39 if (aPerformance.audience > 30)
40 {
41 result += 1000 * (aPerformance.audience - 30);
42 }
43
44 break;
45 case "comedy":
46 result = 30000;
47 if (aPerformance.audience > 20)
48 {
49 result += 1000 + 500 * (aPerformance.audience - 20);
50 }
51
52 break;
53 default:
54 throw new Exception($"unknown type:{play.type}");
55 }
56
57 return result;
58 }
View Code
本篇完成...待续....
标签：重构,play,perf,C#,thisAmount,案例,audience,result,string From： https://www.cnblogs.com/flylittlebaby/p/17202719.html