每次写博客，第一句话都是这样的：程序员很苦逼，除了会写程序，还得会写博客！当然，希望将来的一天，某位老板看到此博客，给你的程序员职工加点薪资吧！因为程序员的世界除了苦逼就是沉默。我眼中的程序员大多都不爱说话，默默承受着编程的巨大压力，除了技术上的交流外，他们不愿意也不擅长和别人交流，更不乐意任何人走进他们的内心！
最近悟出来一个道理，在这儿分享给大家：学历代表你的过去，能力代表你的现在，学习代表你的将来。我们都知道计算机技术发展日新月异，速度惊人的快，你我稍不留神，就会被慢慢淘汰！因此：每日不间断的学习是避免被淘汰的不二法宝。
当然，题外话说多了，咱进入正题！
引言
随着近年来Android和IOS的流行，越来越多的项目需要处理JSON格式数据，因此：学习JSON相关知识成为了程序员必不可少的一门学术。
本文以C#语言，针对JSON入手，简要探讨下JSON数据的处理。
误区
1、很多类型数据都可以转化为JSON，譬如：List集合转化为Json、DataTable转化为Json、XML转化为Json等
2、但是如果反过来转化是否可以呢？譬如：JSON字符串转为DataTable，转为XML，转为LIST等？
在此：我给的答案是(1)中转化不会出现问题，(2)中转化就不一定完全正确了。究其原因，是因为JSON格式多种多样，其他数据类型则对结构有所要求！
例如：DataTable表结构，由列和行组成，稍微复杂的JSON串转化为DataTable就会出错。
在此分享一个JSON转为DataTable的方法，大家自行实验，而实验的结果是运行抛出异常，运行报错。代码如下：
protected void Page_Load(object sender, EventArgs e) { string s = @"{'calledList':[{'duration':0,'id':1,'isCalled':true,'isDel':false,'lDate':1423300697418,'name':'杨秀英','number':'13087237088'},{'duration':0,'id':3,'isCalled':true,'isDel':false,'lDate':1473300711441,'name':'付五爱','number':'15898579759'},{'duration':0,'id':4,'isCalled':true,'isDel':false,'lDate':1473301518397,'name':'梁清华','number':'12467320223'},{'duration':0,'id':5,'isCalled':true,'isDel':false,'lDate':1423301571910,'name':'莫春梅','number':'13273209401'}],'counterid':'A-HN-CS-0731-CT023'}"; DataTable dt = JsonToDataTable(s); } /// <summary> /// 将json转换为DataTable /// </summary> /// <param name="strJson">得到的json 注意：对JSON的格式有要求 否则异常</param> /// <returns></returns> public DataTable JsonToDataTable(string strJson) { //转换json格式 strJson = strJson.Replace(",\"", "*\"").Replace("\":", "\"#").ToString(); //取出表名 var rg = new Regex(@"(?<={)[^:]+(?=:\[)", RegexOptions.IgnoreCase); string strName = rg.Match(strJson).Value; DataTable tb = null; //去除表名 strJson = strJson.Substring(strJson.IndexOf("[") + 1); strJson = strJson.Substring(0, strJson.IndexOf("]")); //获取数据 rg = new Regex(@"(?<={)[^}]+(?=})"); MatchCollection mc = rg.Matches(strJson); for (int i = 0; i < mc.Count; i++) { string strRow = mc[i].Value; string[] strRows = strRow.Split('*'); //创建表 if (tb == null) { tb = new DataTable(); tb.TableName = strName; foreach (string str in strRows) { var dc = new DataColumn(); string[] strCell = str.Split('#'); if (strCell[0].Substring(0, 1) == "\"") { int a = strCell[0].Length; dc.ColumnName = strCell[0].Substring(1, a - 2); } else { dc.ColumnName = strCell[0]; } tb.Columns.Add(dc); } tb.AcceptChanges(); } //增加内容 DataRow dr = tb.NewRow(); for (int r = 0; r < strRows.Length; r++) { dr[r] = strRows[r].Split('#')[1].Trim().Replace("，", ",").Replace("：", ":").Replace("\"", ""); } tb.Rows.Add(dr); tb.AcceptChanges(); } return tb; }
由上实例可知：字符串s的结构要比单纯的DataTable复杂多了，因此：要想将字符串s转为DataTable是行不通的。
那么，我们应当怎样转化JSON呢？在这里给大家介绍一个通用的方法，如下：
不管多么复杂的JSON串，其结构都是有规律可循的，上述中的s字符串无非是由：calledlist集合和属性counterid组成，因此，我们可根据分析的JSON结构，创建如下相关类：
public class callBackList { public string counterid { get; set; } public List<calledList> calledList { get; set; } } public class calledList { public int duration { get; set; } public int id { get; set; } public bool isCalled { get; set; } public bool isDel { get; set; } public long lDate { get; set; } public string name { get; set; } public string number { get; set; } }
在此：会用到一个通用的方法如下：
public T JsonDeserialize<T>(string jsonString) { return JsonConvert.DeserializeObject<T>(jsonString); }
调用实例如下：
protected void Page_Load(object sender, EventArgs e) { string s = @"{'calledList':[{'duration':0,'id':1,'isCalled':true,'isDel':false,'lDate':1473300697418,'name':'杨秀英','number':'13087237088'},{'duration':0,'id':3,'isCalled':true,'isDel':false,'lDate':1473300711441,'name':'付五爱','number':'15898579759'},{'duration':0,'id':4,'isCalled':true,'isDel':false,'lDate':1473301518397,'name':'梁清华','number':'13467320223'},{'duration':0,'id':5,'isCalled':true,'isDel':false,'lDate':1473301571910,'name':'莫春梅','number':'13873209401'}],'counterid':'A-HN-CS-0731-CT023'}"; callBackList O = JsonDeserialize<callBackList>(s); var Ary = O.calledList; string counterId = O.counterid; foreach (var A in Ary) { Response.Write(A.name); } }
小虎斑们可以自行运行，在此不作过多解释。
刚才上文中提到：其他类型转为JSON都是行的通的，JSON转其他类型不一定行的通，除非JSON结构和所要转为的数据类型一致，否则就会转化出错。
那么，我们如何将其他类型转为JSON字符串呢？
在此：首先贴出一个通用的方法如下：
public class JsonHelper { public static string JsonSerializer<T>(T t) { DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T)); MemoryStream ms = new MemoryStream(); ser.WriteObject(ms, t); string jsonString = Encoding.UTF8.GetString(ms.ToArray()); ms.Close(); //替换Json的Date字符串 string p = @"\\/Date\((\d+)\+\d+\)\\/"; MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertJsonDateToDateString); Regex reg = new Regex(p); jsonString = reg.Replace(jsonString, matchEvaluator); return jsonString; } public static T JsonDeserialize<T>(string jsonString) { return JsonConvert.DeserializeObject<T>(jsonString); } /// <summary> /// 将Json序列化的时间由/Date(1294499956278+0800)转为字符串 /// </summary> private static string ConvertJsonDateToDateString(Match m) { string result = string.Empty; DateTime dt = new DateTime(1970, 1, 1); dt = dt.AddMilliseconds(long.Parse(m.Groups[1].Value)); dt = dt.ToLocalTime(); result = dt.ToString("yyyy-MM-dd HH:mm:ss"); return result; } /// <summary> /// 将时间字符串转为Json时间 /// </summary> private static string ConvertDateStringToJsonDate(Match m) { string result = string.Empty; DateTime dt = DateTime.Parse(m.Groups[0].Value); dt = dt.ToUniversalTime(); TimeSpan ts = dt - DateTime.Parse("1970-01-01"); result = string.Format("\\/Date({0}+0800)\\/", ts.TotalMilliseconds); return result; } }
上述方法：JsonSerializer<T>(T t)中的T就是通用类型，可以为DataTable XML OBJECT等
至于其他方法，都是针对专门的类型就行构造的，如下
public class JsonHelper { #region List转化为Json /// <summary> /// List转成json /// </summary> /// <typeparam name="T"></typeparam> /// <param name="jsonName"></param> /// <param name="list"></param> /// <returns></returns> public static string ListToJson<T>(IList<T> list, string jsonName) { StringBuilder Json = new StringBuilder(); if (string.IsNullOrEmpty(jsonName)) jsonName = list[0].GetType().Name; Json.Append("{\"" + jsonName + "\":["); if (list.Count > 0) { for (int i = 0; i < list.Count; i++) { T obj = Activator.CreateInstance<T>(); PropertyInfo[] pi = obj.GetType().GetProperties(); Json.Append("{"); for (int j = 0; j < pi.Length; j++) { Type type = pi[j].GetValue(list[i], null).GetType(); Json.Append("\"" + pi[j].Name.ToString() + "\":" + StringFormat(pi[j].GetValue(list[i], null).ToString(), type)); if (j < pi.Length - 1) { Json.Append(","); } } Json.Append("}"); if (i < list.Count - 1) { Json.Append(","); } } } Json.Append("]}"); return Json.ToString(); } /// <summary> /// List转成json /// </summary> /// <typeparam name="T"></typeparam> /// <param name="list"></param> /// <returns></returns> public static string ListToJson<T>(IList<T> list) { object obj = list[0]; return ListToJson<T>(list, obj.GetType().Name); } #endregion #region 对象转化为Json /// <summary> /// 对象转换为Json字符串 /// </summary> /// <param name="jsonObject">对象</param> /// <returns>Json字符串</returns> public static string ToJson(object jsonObject) { string jsonString = "{"; PropertyInfo[] propertyInfo = jsonObject.GetType().GetProperties(); for (int i = 0; i < propertyInfo.Length; i++) { object objectValue = propertyInfo[i].GetGetMethod().Invoke(jsonObject, null); string value = string.Empty; if (objectValue is DateTime || objectValue is Guid || objectValue is TimeSpan) { value = "'" + objectValue.ToString() + "'"; } else if (objectValue is string) { value = "'" + ToJson(objectValue.ToString()) + "'"; } else if (objectValue is IEnumerable) { value = ToJson((IEnumerable)objectValue); } else { value = ToJson(objectValue.ToString()); } jsonString += "\"" + ToJson(propertyInfo[i].Name) + "\":" + value + ","; } jsonString.Remove(jsonString.Length - 1, jsonString.Length); return jsonString + "}"; } #endregion #region 对象集合转化为Json /// <summary> /// 对象集合转换Json /// </summary> /// <param name="array">集合对象</param> /// <returns>Json字符串</returns> public static string ToJson(IEnumerable array) { string jsonString = "["; foreach (object item in array) { jsonString += ToJson(item) + ","; } jsonString.Remove(jsonString.Length - 1, jsonString.Length); return jsonString + "]"; } /// <summary> /// 普通集合转换Json /// </summary> /// <param name="array">集合对象</param> /// <returns>Json字符串</returns> public static string ToArrayString(IEnumerable array) { string jsonString = "["; foreach (object item in array) { jsonString = ToJson(item.ToString()) + ","; } jsonString.Remove(jsonString.Length - 1, jsonString.Length); return jsonString + "]"; } #endregion #region DataTable转化为Json /// <summary> /// Datatable转换为Json /// </summary> /// <param name="table">Datatable对象</param> /// <returns>Json字符串</returns> public static string ToJson(DataTable dt) { StringBuilder jsonString = new StringBuilder(); if (dt.Rows.Count == 0) { jsonString.Append("[{}]"); return jsonString.ToString(); } jsonString.Append("["); DataRowCollection drc = dt.Rows; for (int i = 0; i < drc.Count; i++) { jsonString.Append("{"); for (int j = 0; j < dt.Columns.Count; j++) { string strKey = dt.Columns[j].ColumnName; string strValue = drc[i][j].ToString(); Type type = dt.Columns[j].DataType; jsonString.Append("\"" + strKey + "\":"); strValue = StringFormat(strValue, type); if (j < dt.Columns.Count - 1) { jsonString.Append(strValue + ","); } else { jsonString.Append(strValue); } } jsonString.Append("},"); } jsonString.Remove(jsonString.Length - 1, 1); jsonString.Append("]"); return jsonString.ToString(); } /// <summary> /// DataTable转成Json /// </summary> /// <param name="jsonName"></param> /// <param name="dt"></param> /// <returns></returns> public static string ToJson(DataTable dt, string jsonName) { StringBuilder Json = new StringBuilder(); if (string.IsNullOrEmpty(jsonName)) jsonName = dt.TableName; Json.Append("{\"" + jsonName + "\":["); if (dt.Rows.Count > 0) { for (int i = 0; i < dt.Rows.Count; i++) { Json.Append("{"); for (int j = 0; j < dt.Columns.Count; j++) { Type type = dt.Rows[i][j].GetType(); Json.Append("\"" + dt.Columns[j].ColumnName.ToString() + "\":" + StringFormat(dt.Rows[i][j].ToString(), type)); if (j < dt.Columns.Count - 1) { Json.Append(","); } } Json.Append("}"); if (i < dt.Rows.Count - 1) { Json.Append(","); } } } Json.Append("]}"); return Json.ToString(); } #endregion #region DataReader转换为Json /// <summary> /// DataReader转换为Json /// </summary> /// <param name="dataReader">DataReader对象</param> /// <returns>Json字符串</returns> public static string ToJson(DbDataReader dataReader) { StringBuilder jsonString = new StringBuilder(); jsonString.Append("["); while (dataReader.Read()) { jsonString.Append("{"); for (int i = 0; i < dataReader.FieldCount; i++) { Type type = dataReader.GetFieldType(i); string strKey = dataReader.GetName(i); string strValue = dataReader[i].ToString(); jsonString.Append("\"" + strKey + "\":"); strValue = StringFormat(strValue, type); if (i < dataReader.FieldCount - 1) { jsonString.Append(strValue + ","); } else { jsonString.Append(strValue); } } jsonString.Append("},"); } dataReader.Close(); jsonString.Remove(jsonString.Length - 1, 1); jsonString.Append("]"); return jsonString.ToString(); } #endregion #region DataSet转换为Json /// <summary> /// DataSet转换为Json /// </summary> /// <param name="dataSet">DataSet对象</param> /// <returns>Json字符串</returns> public static string ToJson(DataSet dataSet) { string jsonString = "{"; foreach (DataTable table in dataSet.Tables) { jsonString += "\"" + table.TableName + "\":" + ToJson(table) + ","; } jsonString = jsonString.TrimEnd(','); return jsonString + "}"; } #endregion #region 过滤特殊字符 /// <summary> /// 过滤特殊字符 /// </summary> /// <param name="s"></param> /// <returns></returns> private static string String2Json(String s) { System.Text.StringBuilder sb = new StringBuilder(); for (int i = 0; i < s.Length; i++) { char c = s.ToCharArray()[i]; switch (c) { case '\"': sb.Append("\\\""); break; case '\\': sb.Append("\\\\"); break; case '/': sb.Append("\\/"); break; case '\b': sb.Append("\\b"); break; case '\f': sb.Append("\\f"); break; case '\n': sb.Append("\\n"); break; case '\r': sb.Append("\\r"); break; case '\t': sb.Append("\\t"); break; default: sb.Append(c); break; } } return sb.ToString(); } #endregion #region 格式化字符型、日期型、布尔型 /// <summary> /// 格式化字符型、日期型、布尔型 /// </summary> /// <param name="str"></param> /// <param name="type"></param> /// <returns></returns> private static string StringFormat(string str, Type type) { if (type == typeof(string)) { str = String2Json(str); str = "\"" + str + "\""; } else if (type == typeof(DateTime)) { str = "\"" + Convert.ToDateTime(str).ToShortDateString() + "\""; } else if (type == typeof(bool)) { str = str.ToLower(); } if (str.Length == 0) str = "\"\""; return str; } #endregion #region XML转化为Json /// <summary> /// XML转化为Json /// </summary> /// <param name="Xml">XML 字符串</param> /// <returns></returns> public static string XML_Json(string Xml) { // To convert an XML node contained in string xml into a JSON string XmlDocument Xmldoc = new XmlDocument(); Xmldoc.LoadXml(Xml); string jsonText = JsonConvert.SerializeXmlNode(Xmldoc); return jsonText; } #endregion /// <summary> /// 生成Json格式 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="obj"></param> /// <returns></returns> public static string GetJson<T>(T obj) { DataContractJsonSerializer json = new DataContractJsonSerializer(obj.GetType()); using (MemoryStream stream = new MemoryStream()) { json.WriteObject(stream, obj); string szJson = Encoding.UTF8.GetString(stream.ToArray()); return szJson; } } /// <summary> /// 获取Json的Model /// </summary> /// <typeparam name="T"></typeparam> /// <param name="szJson"></param> /// <returns></returns> public static T ParseFromJson<T>(string szJson) { T obj = Activator.CreateInstance<T>(); using (MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(szJson))) { DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType()); return (T)serializer.ReadObject(ms); } } }
下班了，不多写了，写的很匆忙。两个JsonHelper，建议大家用上边的，因为所以科学道理，你不用，我也没法~！
@陈卧龙的博客