c#的几个Json库
MiniJSON
SimpleJson
litjson
NewtonJson
其中MiniJSON最简单，所以这边也是学习这个库的Json解析部分（注意：只涉及解析，没有生成json）。
整体代码也没有用到特别的算法什么的，就是一个一个字符的读取，然后根据读到的边界标识符来进行后续的读取，边界标识符的话就是：{}、[]、""、:、,等。
单引号、注释这些的话没有支持，加上各种兼容性估计代码就会复杂很多。
/*
* http://techblog.procurios.nl/k/618/news/view/14605/14863/How-do-I-write-my-own-parser-for-JSON.html
*
* Simplified it so that it doesn't throw exceptions
* and can be used in Unity iPhone with maximum code stripping.
*
*/
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using UnityEngine;
public static class Json
{
/// <summary>
/// Parses the string json into a value
/// </summary>
/// <param name="json">A JSON string.</param>
/// <returns>An List<object>, a Dictionary<string, object>, a double, an integer,a string, null, true, or false</returns>
public static object Deserialize(string json)
{
if (json == null)
return null;
return Parser.Parse(json);
}
private sealed class Parser : IDisposable
{
private const string WORD_BREAK = "{}[],:\"";
private StringReader json;
private Parser(string jsonString)
{
json = new StringReader(jsonString);
}
/// <summary>
/// 探查下一个字符(读指针不变)
/// </summary>
private char PeekChar
{
get { return Convert.ToChar(json.Peek()); }
}
/// <summary>
/// 读下一个字符(读指针往后+1)
/// </summary>
private char NextChar
{
get { return Convert.ToChar(json.Read()); }
}
private string NextWord
{
get
{
var word = new StringBuilder();
while (!IsWordBreak(PeekChar))
{
word.Append(NextChar);
if (json.Peek() == -1)
break;
}
return word.ToString();
}
}
/// <summary>
/// 通过1个字符, 确定标识符, 然后以此确定接下来怎么做
/// </summary>
private TOKEN NextToken
{
get
{
EatWhitespace();
if (json.Peek() == -1)
return TOKEN.NONE;
switch (PeekChar)
{
case '{':
return TOKEN.CURLY_OPEN;
case '}':
json.Read();
return TOKEN.CURLY_CLOSE;
case '[':
return TOKEN.SQUARED_OPEN;
case ']':
json.Read();
return TOKEN.SQUARED_CLOSE;
case ',':
json.Read();
return TOKEN.COMMA;
case '"':
return TOKEN.STRING;
case ':':
return TOKEN.COLON;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '-':
return TOKEN.NUMBER;
}
switch (NextWord)
{
case "false":
return TOKEN.FALSE;
case "true":
return TOKEN.TRUE;
case "null":
return TOKEN.NULL;
}
//jsonStr="abc", 就是none的
return TOKEN.NONE;
}
}
public void Dispose()
{
json.Dispose();
json = null;
}
/// <summary>
/// 断词字符: abc: abc ,abc{, abc}, abc[, abc]等
/// </summary>
public static bool IsWordBreak(char c)
{
return char.IsWhiteSpace(c) || WORD_BREAK.IndexOf(c) != -1;
}
public static object Parse(string jsonString)
{
using (var instance = new Parser(jsonString))
{
return instance.ParseValue();
}
}
private Dictionary<string, object> ParseObject()
{
var table = new Dictionary<string, object>();
// ditch opening brace
json.Read();
// {
while (true)
{
switch (NextToken)
{
case TOKEN.NONE:
// {abc} //不合法object, 得到null
return null;
case TOKEN.COMMA: // {,, "key":1}也不会报错
continue;
case TOKEN.CURLY_CLOSE:
return table;
default:
// {false} //ParseString()拿到空, 然后EatWhiteSpace报错
// {012} // ParseString()拿到012}, 然后EatWhiteSpace报错
// {{}} //报错
// {[]} //报错
// name
var keyName = ParseString();
if (keyName == null)
{
return null;
}
Debug.Log($"'{keyName}'");
// :
if (NextToken != TOKEN.COLON) // {"abc"123}这样的情况, 无效的对象
return null;
// ditch the colon
json.Read();
// value
table[keyName] = ParseValue();
break;
}
}
}
private List<object> ParseArray()
{
var array = new List<object>();
// ditch opening bracket
json.Read();
// [
var parsing = true;
while (parsing)
{
var nextToken = NextToken;
switch (nextToken)
{
case TOKEN.NONE:
// [abc] //不合法array, 得到null
return null;
case TOKEN.COMMA: // {,, 123}不会报错, 最终能得到正确的array
continue;
case TOKEN.SQUARED_CLOSE:
parsing = false;
break;
default:
var value = ParseByToken(nextToken);
array.Add(value);
break;
}
}
return array;
}
//解析json的下一个值(number, bool, string, unicode, null, object, array)
private object ParseValue()
{
var nextToken = NextToken;
return ParseByToken(nextToken);
}
//根据开始token读后面的值
private object ParseByToken(TOKEN token)
{
switch (token)
{
case TOKEN.STRING:
return ParseString();
case TOKEN.NUMBER:
return ParseNumber();
case TOKEN.CURLY_OPEN:
return ParseObject();
case TOKEN.SQUARED_OPEN:
return ParseArray();
case TOKEN.TRUE:
return true;
case TOKEN.FALSE:
return false;
case TOKEN.NULL:
return null;
default:
return null;
}
}
/// <summary>
/// Token为STRING时, 调用该函数才正常
/// </summary>
private string ParseString()
{
var s = new StringBuilder();
char c;
// ditch opening quote
json.Read();
var parsing = true;
while (parsing)
{
if (json.Peek() == -1)
{
parsing = false;
break;
}
c = NextChar;
switch (c)
{
case '"': //结束双引号
parsing = false;
break;
case '\\': // 这样? { "key":"abc\
if (json.Peek() == -1)
{
parsing = false;
break;
}
c = NextChar;
switch (c)
{
case '"': // \"就是Append(")
case '\\': // \\就是Append(\)
case '/': // \/就是Append(/)
s.Append(c);
break;
case 'b':
s.Append('\b');
break;
case 'f':
s.Append('\f');
break;
case 'n':
s.Append('\n'); //linux换行
break;
case 'r':
s.Append('\r'); //mac换行
break;
case 't':
s.Append('\t'); //tab
break;
case 'u': // "\u012"会报错
var hex = new char[4];
for (var i = 0; i < 4; i++)
hex[i] = NextChar;
s.Append((char)Convert.ToInt32(new string(hex), 16));
break;
}
break;
default:
s.Append(c);
break;
}
}
Debug.Log($"ParseString: {s.ToString()}");
return s.ToString();
}
private object ParseNumber()
{
var number = NextWord;
// {"abc": 1-23}, 不会报错, 会得到abc的值为0
if (number.IndexOf('.') == -1)
{
long parsedInt;
long.TryParse(number, out parsedInt);
Debug.Log($"ParseNumber: str:{number}, val:{parsedInt}");
return parsedInt;
}
double parsedDouble;
double.TryParse(number, out parsedDouble);
Debug.Log($"ParseNumber: str:{number}, val:{parsedDouble}");
return parsedDouble;
}
private void EatWhitespace()
{
while (char.IsWhiteSpace(PeekChar))
{
json.Read();
if (json.Peek() == -1)
break;
}
}
private enum TOKEN
{
NONE,
CURLY_OPEN, // {
CURLY_CLOSE, // }
SQUARED_OPEN, // [
SQUARED_CLOSE, // ]
COLON, // :
COMMA, // ,
STRING, // "
NUMBER, // 负号或数字
TRUE, // true
FALSE, // false
NULL, // null
};
}
}
参考
用C#实现一个迷你json库，无需引入dll（可直接放到Unity中使用）_林新发的博客-CSDN博客
【Unity游戏开发】跟着马三一起魔改LitJson - 马三小伙儿 - 博客园 (cnblogs.com)
标签：case,return,TOKEN,private,break,json,源码,解析 From： https://www.cnblogs.com/sailJs/p/17597570.html