[C#] 一個有關於自定字串找尋JSON 格式的值 by JSON.net
2012-10-05
最近公司專案很多，需求也都很詭異..
所以需要這樣的東西，紀錄一下，有需要的人就拿去用吧…
只是寫得不好的部分，也請多多指教…
看一下JSON 資料..
{"Son":{"Son":null,"Name":"D-Son","Friends":null},"Name":"D1","Friends":[{"Son":null,"Name":"D1-1","Friends":[{"Son":null,"Name":"D1-1-1","Friends":null}]},{"Son":null,"Name":"D1-2","Friends":null}]}
{"Name":"D1",
"Son":{"Son":null,"Name":"D-Son","Friends":null},
"Friends":
[
{
"Name":"D1-1",
"Son":null,
"Friends":
[
{
"Name":"D1-1-1",
"Son":null,
"Friends":null
}
]
},{
"Name":"D1-2",
"Son":null,
"Friends":null}]
}
簡單的說 物件結構
D1 的 Son 是 D-Son
D1 的朋友 有 D1-1 , D1-2
D1-1 的朋友 有 D1-1-1
專案的需求就是 如果 我要 取得 D1-1-1 是否我可以直接這樣下指令
"Friends[0].Friends[0].Name"
/// <summary>
/// 透過自訂字串去搜尋JSON 語法
/// </summary>
/// <param name="expressionString">自訂字串</param>
/// <param name="jsonString">JSON format string</param>
/// <returns></returns>
public string GetJsonValueByCustomExpression(string expressionString, string jsonString)
{
var res = jsonString;
foreach (var p in expressionString.Split('.'))
{
//因為意外可能太多、所以直接回傳null
try
{
if (p.Contains("[") && p.Contains("]"))
{
var startIndex = p.IndexOf('[') + 1;
var endIndex = p.IndexOf(']') - p.IndexOf('[') - 1;
int num = int.Parse(p.Substring(startIndex, endIndex));
var q = p.Substring(0, p.IndexOf('['));
JObject tmp = JObject.Parse(res);
res = tmp[q][num].ToString();
}
else
{
JObject tmp = JObject.Parse(res);
res = tmp[p].ToString();
}
}
catch
{
return "";
}
}
return res;
}
這時候看一下我呼叫結果..
string pattern = "Name";
Response.Write(GetJsonValueByCustomExpression(pattern, jsonStr)+"<br />");
//D1
pattern = "Son.Name";
Response.Write(GetJsonValueByCustomExpression(pattern, jsonStr) + "<br />");
//D-Son
pattern = "Friends[0].Friends[0].Name";
Response.Write(GetJsonValueByCustomExpression(pattern, jsonStr) + "<br />");
//D1-1-1
pattern = "Friends[1].Name";
Response.Write(GetJsonValueByCustomExpression(pattern, jsonStr) + "<br />");
//D1-2對了專案需要用到JSON.net 需引入..