一.准备需转为json的数据
在数据库中执行一段SQL返回的数据
需转换后的JSON字符串的效果
[{"TechName":"开料","ItemName":"综合利用率是否为最高","ItemPara":"/"},{"TechName":"开料","ItemName":"综合利用率","ItemPara":"68.36"},{"TechName":"开料","ItemName":"纬向余料","ItemPara":"0"},{"TechName":"开料","ItemName":"经向余料","ItemPara":"0"},{"TechName":"开料","ItemName":"是否为小交货面积拼板","ItemPara":"n"},{"TechName":"开料","ItemName":"纬向尺寸","ItemPara":"24"},{"TechName":"开料","ItemName":"是否为阴阳铜结构","ItemPara":"N"},{"TechName":"开料","ItemName":"是否横竖开料","ItemPara":"N"},{"TechName":"开料","ItemName":"生产尺寸长","ItemPara":"24"},{"TechName":"开料","ItemName":"生产尺寸宽","ItemPara":"18"},{"TechName":"开料","ItemName":"拼板利用率","ItemPara":"68.36"},{"TechName":"开料","ItemName":"开料图纸","ItemPara":"/"},{"TechName":"开料","ItemName":"是否顾客指定板材","ItemPara":"N"},{"TechName":"开料","ItemName":"开料数","ItemPara":"4"},{"TechName":"开料","ItemName":"大料经向尺寸","ItemPara":"36"},{"TechName":"开料","ItemName":"大料纬向尺寸","ItemPara":"48"},{"TechName":"开料","ItemName":"成品尺寸长","ItemPara":"12"},{"TechName":"开料","ItemName":"成品尺寸宽","ItemPara":"13.5"},{"TechName":"开料","ItemName":"是否为PTFE板材","ItemPara":"N"},{"TechName":"开料","ItemName":"交货拼板个数","ItemPara":"1"},{"TechName":"开料","ItemName":"生产拼板个数","ItemPara":"1176"},{"TechName":"开料","ItemName":"交货单位","ItemPara":"U"},{"TechName":"开料","ItemName":"是否为凹蚀板材","ItemPara":"N"}]
二.C#写SQL SERVER(CLR)转JSON函数
先执行SQL返回DataTable,接着再将DataTable转为Json, 这里转为Json有2种方法,代码都贴在下方了
/// <summary> /// 执行SQL语句 返回的DataTable 转为 Json /// </summary> /// <param name="StrSQL"></param> /// <returns></returns> [Microsoft.SqlServer.Server.SqlFunction(DataAccess = DataAccessKind.Read)] public static string ExecSQL2Json(string StrSQL) { DataTable dt = getDataTable(StrSQL); //return DataTable2Json(dt); //方法1 转为 Json if (dt is null) return null; List<Dictionary<string, object>> list = new List<Dictionary<string, object>>(); foreach (DataRow dr in dt.Rows) { Dictionary<string, object> result = new Dictionary<string, object>(); foreach (DataColumn dc in dt.Columns) { result.Add(dc.ColumnName, dr[dc].ToString()); } list.Add(result); } return Json.Serialize(list);//方法2 转为 Json } /// <summary> /// 执行SQL获取DataTable /// </summary> /// <param name="StrSQL"></param> /// <returns></returns> private static DataTable getDataTable(string StrSQL) { DataTable dt = new DataTable(); try { using (SqlConnection cn = new SqlConnection("context connection=true")) { using (SqlDataAdapter da = new SqlDataAdapter(StrSQL, cn)) { DataSet ds = new DataSet(); da.Fill(ds, "tab"); dt = ds.Tables["tab"]; } } } catch (Exception ex) { throw; } return dt; }
方法一：DataTable转Json
/// <summary> /// DataTable转Json /// </summary> /// <param name="table"></param> /// <returns></returns> public static string DataTable2Json(DataTable table) { var JsonString = new StringBuilder(); if (table.Rows.Count > 0) { JsonString.Append("["); for (int i = 0; i < table.Rows.Count; i++) { JsonString.Append("{"); for (int j = 0; j < table.Columns.Count; j++) { object ValueNull = table.Rows[i][j]; if (ValueNull == DBNull.Value) { JsonString.Append("\"" + table.Columns[j].ColumnName.ToString() + "\":null" + ((j < table.Columns.Count - 1) ? "," : "")); } else { string Value = table.Rows[i][j].ToString(); if (table.Columns[j].DataType == typeof(string) || table.Columns[j].DataType == typeof(DateTime) || table.Columns[j].DataType == typeof(Guid)) { JsonString.Append("\"" + table.Columns[j].ColumnName.ToString() + "\":" + "\"" + Value + "\"" + ((j < table.Columns.Count - 1) ? "," : "")); } else { if (table.Columns[j].DataType == typeof(bool)) Value = Value.ToLower(); JsonString.Append("\"" + table.Columns[j].ColumnName.ToString() + "\":" + Value + ((j < table.Columns.Count - 1) ? "," : "")); } } } JsonString.Append("}" + ((i < table.Rows.Count - 1) ? "," : "")); } JsonString.Append("]"); } return JsonString.ToString(); }
方法二: 开源MiniJSON类解析Json字符串
using System; using System.Collections; using System.Collections.Generic; using System.IO; using System.Linq; using System.Text; namespace SQLClr { /// <summary> /// This class encodes and decodes JSON strings. /// Spec. details, see http://www.json.org/ /// /// JSON uses Arrays and Objects. These correspond here to the datatypes IList and IDictionary. /// All numbers are parsed to doubles. /// </summary> 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> //反序列化 public static object Deserialize(string json) { // save the string for debug information if (json == null) { return null; } return Parser.Parse(json); } //阻止其他类从该类继承 sealed class Parser : IDisposable { const string WORD_BREAK = "{}[],:\""; public static bool IsWordBreak(char c) { // 如果 c 是空白，则为 true；否则，为 false;报告指定 Unicode 字符在此字符串中的第一个匹配项的索引。 return Char.IsWhiteSpace(c) || WORD_BREAK.IndexOf(c) != -1; } enum TOKEN { NONE, CURLY_OPEN, CURLY_CLOSE, SQUARED_OPEN, SQUARED_CLOSE, COLON, COMMA, STRING, NUMBER, TRUE, FALSE, NULL }; // 实现从字符串进行读取的 System.IO.TextReader。 StringReader json; Parser(string jsonString) { json = new StringReader(jsonString); } public static object Parse(string jsonString) { using (var instance = new Parser(jsonString)) { return instance.ParseValue(); } } //释放 public void Dispose() { json.Dispose(); json = null; } Dictionary<string, object> ParseObject() { Dictionary<string, object> table = new Dictionary<string, object>(); // ditch opening brace json.Read(); // { while (true) { switch (NextToken) { case TOKEN.NONE: return null; case TOKEN.COMMA: continue; case TOKEN.CURLY_CLOSE: return table; default: // name string name = ParseString(); if (name == null) { return null; } // : if (NextToken != TOKEN.COLON) { return null; } // ditch the colon json.Read(); // value table[name] = ParseValue(); break; } } } List<object> ParseArray() { List<object> array = new List<object>(); // ditch opening bracket json.Read(); // [ bool parsing = true; while (parsing) { TOKEN nextToken = NextToken; switch (nextToken) { case TOKEN.NONE: return null; case TOKEN.COMMA: continue; case TOKEN.SQUARED_CLOSE: parsing = false; break; default: object value = ParseByToken(nextToken); array.Add(value); break; } } return array; } object ParseValue() { TOKEN nextToken = NextToken; return ParseByToken(nextToken); } 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; } } string ParseString() { StringBuilder s = new StringBuilder(); char c; // ditch opening quote json.Read(); bool parsing = true; while (parsing) { if (json.Peek() == -1) { parsing = false; break; } c = NextChar; switch (c) { case '"': parsing = false; break; case '\\': if (json.Peek() == -1) { parsing = false; break; } c = NextChar; switch (c) { case '"': case '\\': case '/': s.Append(c); break; case 'b': s.Append('\b'); break; case 'f': s.Append('\f'); break; case 'n': s.Append('\n'); break; case 'r': s.Append('\r'); break; case 't': s.Append('\t'); break; case 'u': var hex = new char[4]; for (int i = 0; i < 4; i++) { hex[i] = NextChar; } s.Append((char)Convert.ToInt32(new string(hex), 16)); break; } break; default: s.Append(c); break; } } return s.ToString(); } object ParseNumber() { string number = NextWord; // 摘要: // 报告指定 Unicode 字符在此字符串中的第一个匹配项的索引。 // // 参数: // value: // 要查找的 Unicode 字符。 // // 返回结果: // 如果找到该字符，则为 value 的从零开始的索引位置；如果未找到，则为 -1。 if (number.IndexOf('.') == -1) { long parsedInt; // 将数字的字符串表示形式转换为它的等效 64 位有符号整数。一个指示转换是否成功的返回值。 Int64.TryParse(number, out parsedInt); return parsedInt; } double parsedDouble; Double.TryParse(number, out parsedDouble); return parsedDouble; } // void EatWhitespace() { //指示指定字符串中位于指定位置处的字符是否属于空白类别。 while (Char.IsWhiteSpace(PeekChar)) { json.Read(); //摘要: // 返回下一个可用的字符，但不使用它。 // // 返回结果: // 表示下一个要读取的字符的整数，或者，如果没有更多的可用字符或该流不支持查找，则为 -1。 if (json.Peek() == -1) { break; } } } char PeekChar { get { // 读取输入字符串中的下一个字符并将该字符的位置提升一个字符。 // // 返回结果: // 基础字符串中的下一个字符，或者如果没有更多的可用字符，则为 -1。 return Convert.ToChar(json.Peek()); } } char NextChar { get { return Convert.ToChar(json.Read()); } } string NextWord { get { // 表示可变字符字符串。无法继承此类。 StringBuilder word = new StringBuilder(); while (!IsWordBreak(PeekChar)) { // 摘要: // 在此实例的结尾追加指定 Unicode 字符的字符串表示形式。 // // 参数: // value: // 要追加的 Unicode 字符。 // // 返回结果: // 完成追加操作后对此实例的引用。 word.Append(NextChar); //下一个字符为空 if (json.Peek() == -1) { break; } } // return word.ToString(); } } 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; } return TOKEN.NONE; } } } /// <summary> /// Converts a IDictionary / IList object or a simple type (string, int, etc.) into a JSON string /// </summary> /// <param name="json">A Dictionary<string, object> / List<object></param> /// <returns>A JSON encoded string, or null if object 'json' is not serializable</returns> public static string Serialize(object obj) { return Serializer.Serialize(obj); } sealed class Serializer { StringBuilder builder; Serializer() { //创建生成器 builder = new StringBuilder(); } //序列化 public static string Serialize(object obj) { var instance = new Serializer(); instance.SerializeValue(obj); return instance.builder.ToString(); } //类型 void SerializeValue(object value) { IList asList; IDictionary asDict; string asStr; if (value == null) { builder.Append("null"); } else if ((asStr = value as string) != null) { SerializeString(asStr); } else if (value is bool) { builder.Append((bool)value ? "true" : "false"); } else if ((asList = value as IList) != null) { SerializeArray(asList); } else if ((asDict = value as IDictionary) != null) { SerializeObject(asDict); } else if (value is char) { SerializeString(new string((char)value, 1)); } else { SerializeOther(value); } } //序列化对象 void SerializeObject(IDictionary obj) { bool first = true; builder.Append('{'); foreach (object e in obj.Keys) { if (!first) { builder.Append(','); } SerializeString(e.ToString()); builder.Append(':'); SerializeValue(obj[e]); first = false; } builder.Append('}'); } // 序列化数组 void SerializeArray(IList anArray) { builder.Append('['); bool first = true; foreach (object obj in anArray) { if (!first) { builder.Append(','); } SerializeValue(obj); first = false; } builder.Append(']'); } //string void SerializeString(string str) { builder.Append('\"'); char[] charArray = str.ToCharArray(); foreach (var c in charArray) { switch (c) { case '"': builder.Append("\\\""); break; case '\\': builder.Append("\\\\"); break; case '\b': builder.Append("\\b"); break; case '\f': builder.Append("\\f"); break; case '\n': builder.Append("\\n"); break; case '\r': builder.Append("\\r"); break; case '\t': builder.Append("\\t"); break; default: int codepoint = Convert.ToInt32(c); if ((codepoint >= 32) && (codepoint <= 126)) { builder.Append(c); } else { //builder.Append("\\u"); //builder.Append(codepoint.ToString("x4")); builder.Append(c); } break; } } builder.Append('\"'); } //其他 void SerializeOther(object value) { // NOTE: decimals lose precision during serialization. // They always have, I'm just letting you know. // Previously floats and doubles lost precision too. //注意：小数在序列化过程中丢失精度。 //他们总是有，我只是让你知道。 //以前失去精度和双精度浮点数。 if (value is float) { builder.Append(((float)value).ToString("R")); } else if (value is int || value is uint || value is long || value is sbyte || value is byte || value is short || value is ushort || value is ulong) { builder.Append(value); } else if (value is double || value is decimal) { builder.Append(Convert.ToDouble(value).ToString("R")); } else { SerializeString(value.ToString()); } } } } }
三.SQL服务器CLR配置（允许SQL调用.net程序）
sp_configure 'show advanced options', 1; RECONFIGURE WITH override GO sp_configure 'clr enabled', 1; RECONFIGURE WITH override GO Sp_changedbowner 'sa',true --sa改为当前登入用户名 alter database [dbname] set trustworthy on --bbname 改为自己的库名
四.注册 CLR 程序集
create ASSEMBLY SQLfunctionAssembly FROM 'D:\SQLClr.dll' --改为自己C#写的dll路径填写 WITH PERMISSION_SET = UNSAFE;
创建的.net程序集数据会写入下表：
select * from sys.assemblies select * from sys.assembly_files
五.创建标量函数
create FUNCTION [dbo].[ExecSQL2Json](@StrSQL [nvarchar](max)) RETURNS [nvarchar](max) WITH EXECUTE AS CALLER AS EXTERNAL NAME [SQLfunctionAssembly].[SQLClr.SQLfunction].[ExecSQL2Json]
六.测试转Json函数
DECLARE @SQL VARCHAR(MAX) SET @SQL = 'SELECT TechName,ItemName,ItemPara FROM FP_EMS_DB.dbo.V_ppegeneral WHERE pdctno = ''2V011Z30A4'' AND TechNo = ''CC_01'' ORDER BY ItemNo ' SELECT dbo.ExecSQL2Json(@SQL)
运行后结果
七.小结
采用CLR方式写SQL SERVER函数转为json字符串，那么只要传入一段SQL语句就可以转为Json字符串，是不是很方便，但这种作法在实际应用中作用不太大,因为业务系统现在基本采用ORM 对象关系映射模型开发,数据库表映射成对象，直接操作的对象，然而对象转为json放在应用程序端转换是及为方便的，在这里只开拓一种新思路在数据库中实现转json的方法。