[原创]
https://www.cnblogs.com/gangjian/p/14386552.html
public class JSONReader
{
// 从文件读出JSON对象
public static JSONObject Read(string path)
{
if (!File.Exists(path))
{
return null;
}
try
{
string txt = File.ReadAllText(path);
int offset = 0;
JSONObject obj = null;
if (JSONObject.TryParse(txt, ref offset, out obj))
{
return obj;
}
}
catch (Exception)
{
}
return null;
}
}
public class JSONObject
{
// JSON对象
List<JSONPair> _pairs = new List<JSONPair>(); // '名称:值'对list
private JSONObject(List<JSONPair> pair_list)
{
this._pairs = pair_list;
}
public static bool TryParse(string in_str, ref int offset, out JSONObject obj)
{
obj = null;
int idx = offset;
char? ch = Util.GetNextNsChar(in_str, ref idx);
if (null == ch
|| !ch.Equals('{'))
{
return false;
}
idx += 1;
List<JSONPair> pair_list = new List<JSONPair>();
while (true)
{
JSONPair pair;
if (JSONPair.TryParse(in_str, ref idx, out pair))
{
pair_list.Add(pair);
idx += 1;
}
ch = Util.GetNextNsChar(in_str, ref idx);
if (null != ch)
{
if (ch.Equals('}'))
{
// 结束
obj = new JSONObject(pair_list);
offset = idx;
return true;
}
else if (ch.Equals(','))
{
idx += 1;
continue;
}
}
break;
}
return false;
}
}
public class JSONArray
{
// JSON数组
List<JSONValue> _valList = new List<JSONValue>();
internal List<JSONValue> ValueList
{
get { return _valList; }
}
private JSONArray(List<JSONValue> val_list)
{
this._valList = val_list;
}
public static bool TryParse(string in_str, ref int offset, out JSONArray array)
{
array = null;
int idx = offset;
char? ch = Util.GetNextNsChar(in_str, ref idx);
if (null == ch
|| !ch.Equals('['))
{
return false;
}
idx += 1;
List<JSONValue> val_list = new List<JSONValue>();
while (true)
{
JSONValue val;
if (JSONValue.TryParse(in_str, ref idx, out val))
{
val_list.Add(val);
idx += 1;
}
ch = Util.GetNextNsChar(in_str, ref idx);
if (null != ch)
{
if (ch.Equals(']'))
{
// 结束
array = new JSONArray(val_list);
offset = idx;
return true;
}
else if (ch.Equals(','))
{
idx += 1;
continue;
}
}
break;
}
return false;
}
}
public class JSONPair
{
// '名称:值'对
string _name = string.Empty;
object _value = null;
private JSONPair(string name, JSONValue val)
{
this._name = name;
this._value = val;
}
public static bool TryParse(string in_str, ref int offset, out JSONPair pair)
{
pair = null;
int idx = offset;
string name = Util.GetJsonStr(in_str, ref idx);
if (null == name)
{
return false;
}
idx += 1;
char? ch = Util.GetNextNsChar(in_str, ref idx);
if (null == ch
|| !ch.Equals(':'))
{
return false;
}
idx += 1;
JSONValue val;
if (!JSONValue.TryParse(in_str, ref idx, out val))
{
return false;
}
pair = new JSONPair(name, val);
offset = idx;
return true;
}
}
public class JSONValue
{
// 字符串
// 数字
// JSONObject
// JSONArray
// true/false
// null
object _value = null;
public object Value
{
get { return _value; }
}
string _category = string.Empty;
public string Category
{
get { return _category; }
}
private JSONValue(string category, object val)
{
this._category = category;
this._value = val;
}
public static bool TryParse(string in_str, ref int offset, out JSONValue val)
{
val = null;
int idx = offset;
char? ch = Util.GetNextNsChar(in_str, ref idx);
if (null == ch)
{
return false;
}
else if (ch.Equals('\"'))
{
// 字符串
string str = Util.GetJsonStr(in_str, ref idx);
if (null != str)
{
val = new JSONValue("string", str);
offset = idx;
return true;
}
}
else if (char.IsDigit(Convert.ToChar(ch)))
{
// 数字
string word_str = Util.GetWord(in_str, ref idx);
int ival;
if (null != word_str
&& int.TryParse(word_str, out ival))
{
val = new JSONValue("number", ival);
offset = idx;
return true;
}
}
else if (ch.Equals('{'))
{
// JSON对象
JSONObject obj;
if (JSONObject.TryParse(in_str, ref idx, out obj))
{
val = new JSONValue("JSON Object", obj);
offset = idx;
return true;
}
}
else if (ch.Equals('['))
{
// JSON数组
JSONArray arr;
if (JSONArray.TryParse(in_str, ref idx, out arr))
{
val = new JSONValue("JSON Array", arr);
offset = idx;
return true;
}
}
else
{
// true,false,null
string word = Util.GetWord(in_str, ref idx);
if (word.ToLower().Equals("true"))
{
val = new JSONValue("bool", true);
offset = idx;
return true;
}
else if (word.ToLower().Equals("false"))
{
val = new JSONValue("bool", false);
offset = idx;
return true;
}
else if (word.ToLower().Equals("null"))
{
val = new JSONValue("null", null);
offset = idx;
return true;
}
}
return false;
}
}
class Util
{
public static char? GetNextNsChar(string in_str, ref int offset)
{
char? ret = null;
for (int i = offset; i < in_str.Length; i++)
{
if (char.IsWhiteSpace(in_str[i])
|| in_str[i].Equals('\r')
|| in_str[i].Equals('\n'))
{
}
else
{
offset = i;
return in_str[i] as char?;
}
}
return ret;
}
public static string GetWord(string in_str, ref int offset)
{
StringBuilder sb = new StringBuilder();
for (int i = offset; i < in_str.Length; i++)
{
char ch = in_str[i];
if (char.IsWhiteSpace(ch)
|| ch.Equals('\r')
|| ch.Equals('\n'))
{
if (0 != sb.Length)
{
offset = i - 1;
return sb.ToString();
}
break;
}
else
{
sb.Append(ch);
}
}
return null;
}
public static string GetJsonStr(string in_str, ref int offset)
{
int idx = offset;
char? quote = GetNextNsChar(in_str, ref idx);
if (!quote.Equals('"'))
{
return null;
}
StringBuilder sb = new StringBuilder();
sb.Append(in_str[idx]);
for (int i = idx + 1; i < in_str.Length; i++)
{
char ch = in_str[i];
if (ch.Equals('\r') || ch.Equals('\n'))
{
// 回车换行
break;
}
else if (ch.Equals('\\'))
{
// 转义字符
sb.Append(ch);
if (i + 1 < in_str.Length
&& !in_str[i + 1].Equals('\r')
&& !in_str[i + 1].Equals('\n'))
{
sb.Append(in_str[i + 1]);
i += 1;
}
else
{
break;
}
}
else if (ch.Equals('"'))
{
// 字符串结束
sb.Append(ch);
offset = i;
return sb.ToString();
}
else
{
sb.Append(ch);
}
}
return null;
}
}
参考:
