delphi json生成和解析

delphi json生成和解析

使用DELPHI 自带的JSON类。

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{     "date": "2014-03-04",     "error": 0,     "results": [         {             "currentCity": "成都",             "weather_data": [                 {                     "date": "周二(今天, 实时：12℃)",                     "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/duoyun.png",                     "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/duoyun.png",                     "temperature": "15 ~ 6℃",                     "weather": "多云",                     "wind": "北风微风"                 },                 {                     "date": "周三",                     "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/yin.png",                     "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/xiaoyu.png",                     "temperature": "14 ~ 7℃",                     "weather": "阴转小雨",                     "wind": "北风微风"                 },                 {                     "date": "周四",                     "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/xiaoyu.png",                     "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/xiaoyu.png",                     "temperature": "12 ~ 7℃",                     "weather": "小雨",                     "wind": "北风微风"                 },                 {                     "date": "周五",                     "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/xiaoyu.png",                     "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/xiaoyu.png",                     "temperature": "9 ~ 6℃",                     "weather": "小雨",                     "wind": "南风微风"                 }             ]         }     ],     "status": "success" }

　　

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uses System.JSON var MJsonTxt:string; MJson:TJSONObject ; Value,Value2:string; begin  MJsonTxt :=Memo1.Lines .Text ;  MJson :=TJSONObject .ParseJSONValue(MJsonTxt )as TJSONObject ;  if Assigned(MJson ) then  begin    Value :=MJson .GetValue<string>('results[0].weather_data[1].temperature');      ShowMessage(Value ); //14 ~ 7℃     FreeAndNil(MJson );  end; end;

　

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var jr:tjsonarray;   jr := jo.GetValue<TJSONArray>('data.dataList') ;         for i := 0 to jr.Count - 1 do   begin     jrow := jr.Get(i) as TJSONObject;   self.Caption:=  jrow.GetValue<string>('ampm');   end;

　

 

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uses System.JSON;   procedure TForm1.Button1Click(Sender: TObject); //解析JSON begin   var jo: TJSONObject := TJSONObject.ParseJSONValue('{"name":"张三", "other":["中国","程序员"]}') as TJSONObject;  //从字符串生成JSON   Memo2.Lines.Add('遍历JSON数据：');   Memo2.Lines.Add('JSON数据数量：' + IntToStr(jo.Count));   var tmp: string;   for var i: integer := 0 to jo.Count - 1 do    //1,遍历JSON数据     tmp := tmp + jo.Get(i).ToString;   Memo2.Lines.Add(tmp);   Memo2.Lines.Add('');   Memo2.Lines.Add('按元素解析JSON数据：');  //2,按元素解析JSON数据   tmp := 'name = ' + jo.Values['name'].value;   Memo2.Lines.Add(tmp);   var ja: TJSONArray := TJSONArray(jo.GetValue('other'));   // json数组   tmp := 'other = ' + jo.GetValue('other').ToString + #13#10; // 得到JSON数组字符串   for var i: integer := 0 to ja.Size - 1 do    // 循环取得JSON数组中每个元素     tmp := tmp + IntToStr(i + 1) + ' : ' + ja.Items[i].Value + #13#10;   Memo2.Lines.Add(tmp);   jo.Free; end;   procedure TForm1.Button2Click(Sender: TObject); //生成JSON begin   var jo: TJSONObject := TJSONObject.Create;   jo.AddPair('name','张三');  // var ja: TJSONArray := TJSONObject.ParseJSONValue('["中国","程序员"]') as TJSONArray;   var ja: TJSONArray := TJSONArray.Create;   ja.Add('中国');   ja.Add('程序员');   jo.AddPair('other', ja);   Memo2.Lines.Add(jo.ToString); //{"name":"张三","other":["中国","程序员"]}   Memo2.Lines.Add(jo.ToJSON);   //{"name":"\u5F20\u4E09","other":["\u4E2D\u56FD","\u7A0B\u5E8F\u5458"]}   jo.Free; end;

　　

　

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const   s = '[{"id":1,"name":"咏南"},{"id":2,"name":"中间件"}]';   procedure newFields(const ds: TDataSet; const ja: TJSONArray; const strFieldSize: Integer = 256); begin   var jo: TJSONObject := ja.Items[0] as TJSONObject;   ds.Close;   ds.FieldDefs.Clear;   for var pair: TJSONPair in jo do   begin     var fieldName: string := pair.JsonString.Value;     var fieldSize: Integer := 0;     if pair.JsonValue is TJSONString then     begin       fieldSize := strFieldSize;       ds.FieldDefs.Add(fieldName, ftString, fieldSize)     end     else if pair.JsonValue is TJSONNumber then     begin       ds.FieldDefs.Add(fieldName, ftFloat);     end;   end;   if ds is TClientDataSet then     TClientDataSet(ds).CreateDataSet; end;

　

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procedure TForm2.Button1Click(Sender: TObject); begin   var s: string := '{"name":"咏南中间件","age":12}';   var jo: TJSONObject := TJSONObject.Create;   jo.AddPair('f1', s);   Memo1.Lines.add(jo.ToJSON);   //{"f1":"{\"name\":\"\u548F\u5357\u4E2D\u95F4\u4EF6\",\"age\":12}"}     var jo2: TJSONObject := TJSONObject.ParseJSONValue(jo.ToString) as TJSONObject;   s := jo2.tostring;               //{"f1":"{\"name\":\"咏南中间件\",\"age\":12}"}   s := StringReplace(s, '\"', '"', [rfReplaceAll]);   memo1.Lines.add(s);   //{"f1":"{"name":"咏南中间件","age":12}"}   jo.free;   jo2.free; end;