JSON格式化源代码

  1 public class StringWalker
  2     {
  3         private readonly string _s;
  4
  5         public int Index { get; private set; }
  6         public bool IsEscaped { get; private set; }
  7         public char CurrentChar { get; private set; }
  8
  9         public StringWalker(string s)
 10         {
 11             _s = s;
 12             this.Index = -1;
 13         }
 14
 15         public bool MoveNext()
 16         {
 17             if (this.Index == _s.Length - 1)
 18                 return false;
 19
 20             if (IsEscaped == false)
 21                 IsEscaped = CurrentChar == ‘\\‘;
 22             else
 23                 IsEscaped = false;
 24             this.Index++;
 25             CurrentChar = _s[Index];
 26             return true;
 27         }
 28     };
 29
 30     public class IndentWriter
 31     {
 32         private readonly StringBuilder _result = new StringBuilder();
 33         private int _indentLevel;
 34
 35         public void Indent()
 36         {
 37             _indentLevel++;
 38         }
 39
 40         public void UnIndent()
 41         {
 42             if (_indentLevel > 0)
 43                 _indentLevel--;
 44         }
 45
 46         public void WriteLine(string line)
 47         {
 48             _result.AppendLine(CreateIndent() + line);
 49         }
 50
 51         private string CreateIndent()
 52         {
 53             StringBuilder indent = new StringBuilder();
 54             for (int i = 0; i < _indentLevel; i++)
 55                 indent.Append("    ");
 56             return indent.ToString();
 57         }
 58
 59         public override string ToString()
 60         {
 61             return _result.ToString();
 62         }
 63     };
 64
 65
 66
 67     public class JsonFormatter
 68     {
 69         private readonly StringWalker _walker;
 70         private readonly IndentWriter _writer = new IndentWriter();
 71         private readonly StringBuilder _currentLine = new StringBuilder();
 72         private bool _quoted;
 73
 74         public JsonFormatter(string json)
 75         {
 76             _walker = new StringWalker(json);
 77             ResetLine();
 78         }
 79
 80         public void ResetLine()
 81         {
 82             _currentLine.Length = 0;
 83         }
 84
 85         public string Format()
 86         {
 87             while (MoveNextChar())
 88             {
 89                 if (this._quoted == false && this.IsOpenBracket())
 90                 {
 91                     this.WriteCurrentLine();
 92                     this.AddCharToLine();
 93                     this.WriteCurrentLine();
 94                     _writer.Indent();
 95                 }
 96                 else if (this._quoted == false && this.IsCloseBracket())
 97                 {
 98                     this.WriteCurrentLine();
 99                     _writer.UnIndent();
100                     this.AddCharToLine();
101                 }
102                 else if (this._quoted == false && this.IsColon())
103                 {
104                     this.AddCharToLine();
105                     this.WriteCurrentLine();
106                 }
107                 else
108                 {
109                     AddCharToLine();
110                 }
111             }
112             this.WriteCurrentLine();
113             return _writer.ToString();
114         }
115
116         private bool MoveNextChar()
117         {
118             bool success = _walker.MoveNext();
119             if (this.IsApostrophe())
120             {
121                 this._quoted = !_quoted;
122             }
123             return success;
124         }
125
126         public bool IsApostrophe()
127         {
128             return this._walker.CurrentChar == ‘"‘ && this._walker.IsEscaped == false;
129         }
130
131         public bool IsOpenBracket()
132         {
133             return this._walker.CurrentChar == ‘{‘
134                 || this._walker.CurrentChar == ‘[‘;
135         }
136
137         public bool IsCloseBracket()
138         {
139             return this._walker.CurrentChar == ‘}‘
140                 || this._walker.CurrentChar == ‘]‘;
141         }
142
143         public bool IsColon()
144         {
145             return this._walker.CurrentChar == ‘,‘;
146         }
147
148         private void AddCharToLine()
149         {
150             this._currentLine.Append(_walker.CurrentChar);
151         }
152
153         private void WriteCurrentLine()
154         {
155             string line = this._currentLine.ToString().Trim();
156             if (line.Length > 0)
157             {
158                 _writer.WriteLine(line);
159             }
160             this.ResetLine();
161         }
162     };

测试代码:

1 Console.WriteLine(new JsonFormatter(
2     @"{""parameter"" : ""value"" , { ""parameter2"" : ""value2"" },{ ""parameter3"" : ""value3"" } }").Format());
3 Console.WriteLine(new JsonFormatter(
4     @"{""parameter"":[""value1"",""value2"",""value3""] }").Format());
5 Console.WriteLine(new JsonFormatter(
6     @"{""parameter"": ""value with {brackets}"" }").Format());
7 Console.WriteLine(new JsonFormatter(
8     @"{ ""hello"" : ""value with quotes \""{brackets} and back slash: \\"" }").Format());

运行结果：

 1 {
 2     "parameter" : "value" ,
 3     {
 4         "parameter2" : "value2"
 5     },
 6     {
 7         "parameter3" : "value3"
 8     }
 9 }
10
11 {
12     "parameter":
13     [
14         "value1",
15         "value2",
16         "value3"
17     ]
18 }
19
20 {
21     "parameter": "value with {brackets}"
22 }
23
24 {
25     "hello" : "value with quotes \"{brackets} and back slash: \\"
26 }