利用QJSON将FDQuery转成JSON串

服务器要支持Http协议，打算采用Http+JSON的方式来交换数据。一开始考虑使用superobject，因为以前使用比较多，比较熟悉。

代码如下：

 1 class function FDQueryToSJSON(aQuery : TFDQuery) : string;

 2 

 3 class function TFDQueryJSONReflect.FDQueryToSJSON(aQuery: TFDQuery): string;

 4 var

 5   sj,aj,sj2,aj2:ISuperObject;

 6   i:Integer;

 7   Fieldtyp,JsonTyp:string;

 8   List:TStringList;

 9   aField : TField;

10   Fields : string;

11 begin

12   // 得到一个JSON对象

13   sj := SO();

14   //创建列

15   aj := SA([]);

16   List := TStringList.Create;

17   try

18     List.Sorted := True;

19 

20     Fields := '{';

21     for i := 0 to aQuery.FieldCount - 1 do

22     begin

23       sj2 := SO();

24       GetFieldTypeInfo(aQuery.Fields[i],Fieldtyp,JsonTyp);

25 

26       sj2.S[cstFieldName] := aQuery.Fields[i].FieldName;

27       sj2.S[cstFieldType] := Fieldtyp;

28       sj2.S[cstJsonType] := JsonTyp;

29       sj2.I[cstFieldSize] := aQuery.Fields[i].Size;

30       sj2.B[cstRequired] := aQuery.Fields[i].Required;

31       sj2.I[cstFieldIndex] := aQuery.Fields[i].Index;

32       aj.AsArray.Add(sj2);

33       List.Add(aQuery.Fields[i].FieldName+'='+JsonTyp);

34       Fields := Fields+aQuery.Fields[i].FieldName+':'+'0'+',';

35     end;

36     Fields := Fields.TrimRight([',']);

37     Fields := Fields+'}';

38 

39     sj.O['Fields'] := SO(Fields);

40     sj.O['Cols'] := aj;

41     //创建数据集的数据

42     aQuery.DisableControls;

43     aQuery.First;

44 

45     aj2 := SA([]);

46     while  not aQuery.Eof do

47     begin

48       sj2 := SO();

49       for i := 0 to List.Count - 1 do

50       begin

51         aField := aQuery.Fields.FindField(List.Names[i]);

52 

53         if VarIsNull(aField.Value) then

54           sj2.O[aField.FieldName] := SO(Null)

55         else

56         begin

57           CreateJsonValueByField(sj2,aField);

58         end;

59       end;

60       aj2.AsArray.Add(sj2);

61       aQuery.Next;

62     end;

63    

64     sj.O['Data'] := aj2;

65     Result := sj.AsString;

66   finally

67     List.Free;

68     aQuery.EnableControls;

69   end;

70 end;

 1 class function CreateJsonValueByField(Json:ISuperObject;Field:TField):Boolean; overload;

 2 

 3 class function TFDQueryJSONReflect.CreateJsonValueByField(Json: ISuperObject;

 4   Field: TField): Boolean;

 5 begin

 6   Result := False;

 7   if (Field Is TDateTimeField) or (Field is TSQLTimeStampField) then

 8       Json.O[Field.FieldName] := SO(Field.AsDateTime)

 9   else if Field is TBlobField then

10       Json.S[Field.FieldName] := EncodeString(Field.AsString)

11   else

12       Json.O[Field.FieldName] := SO(Field.Value);

13   Result := True;

14 end;

这样写，没问题，可以得到结果，但是我觉得冗余的数据比较多，有些信息是不需要每行都返回的。比如字段名，每条记录都返回了。

但是当我想去掉Data的字段名时，才注意到JSON串里面的顺序和字段的顺序居然不是一致的，无论我怎么插入，只要是用SuperObject的接口去生成JSON串，

顺序都会被自动按照一种我目前没理解的方式排序。除非我自己用字符串去拼装JSON串。

该方法得到的结果如下：

{"Fields":{"base_schema_ver":0,"sysstat":0,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":0,"refdate":0,"userstat":0,"status":0,"crdate":0,"xtype":0,"indexdel":0,"version":0,"id":0,"stats_schema_ver":0,"seltrig":0,"type":0,"name":0,"info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":0,"instrig":0},"Data":[{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761910,"userstat":1,"status":0,"crdate":1270198761910,"xtype":"S","indexdel":0,"version":0,"id":3,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysrscols","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761277,"userstat":1,"status":0,"crdate":1270198761277,"xtype":"S","indexdel":0,"version":0,"id":5,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysrowsets","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761273,"userstat":1,"status":0,"crdate":1270198761273,"xtype":"S","indexdel":0,"version":0,"id":7,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysallocunits","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1049764417267,"userstat":1,"status":0,"crdate":1049764417267,"xtype":"S","indexdel":0,"version":0,"id":8,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysfiles1","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198762227,"userstat":1,"status":0,"crdate":1270198762227,"xtype":"S","indexdel":0,"version":0,"id":17,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"syspriorities","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761840,"userstat":1,"status":0,"crdate":1270198761840,"xtype":"S","indexdel":0,"version":0,"id":18,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysdbfrag","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761853,"userstat":1,"status":0,"crdate":1270198761853,"xtype":"S","indexdel":0,"version":0,"id":19,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysfgfrag","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761847,"userstat":1,"status":0,"crdate":1270198761847,"xtype":"S","indexdel":0,"version":0,"id":21,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"syspru","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761850,"userstat":1,"status":0,"crdate":1270198761850,"xtype":"S","indexdel":0,"version":0,"id":22,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysbrickfiles","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761857,"userstat":1,"status":0,"crdate":1270198761857,"xtype":"S","indexdel":0,"version":0,"id":23,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysphfg","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761860,"userstat":1,"status":0,"crdate":1270198761860,"xtype":"S","indexdel":0,"version":0,"id":24,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysprufiles","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761360,"userstat":1,"status":0,"crdate":1270198761360,"xtype":"S","indexdel":0,"version":0,"id":25,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysftinds","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761357,"userstat":1,"status":0,"crdate":1270198761357,"xtype":"S","indexdel":0,"version":0,"id":27,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysowners","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761300,"userstat":1,"status":0,"crdate":1270198761300,"xtype":"S","indexdel":0,"version":0,"id":28,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysdbreg","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761267,"userstat":1,"status":0,"crdate":1270198761267,"xtype":"S","indexdel":0,"version":0,"id":29,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysprivs","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761323,"userstat":1,"status":0,"crdate":1270198761323,"xtype":"S","indexdel":0,"version":0,"id":34,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysschobjs","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761520,"userstat":1,"status":0,"crdate":1270198761520,"xtype":"S","indexdel":0,"version":0,"id":39,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"syslogshippers","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761337,"userstat":1,"status":0,"crdate":1270198761337,"xtype":"S","indexdel":0,"version":0,"id":41,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"syscolpars","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761313,"userstat":1,"status":0,"crdate":1270198761313,"xtype":"S","indexdel":0,"version":0,"id":42,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysxlgns","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0},{"base_schema_ver":0,"sysstat":1,"deltrig":0,"parent_obj":0,"schema_ver":0,"uid":4,"refdate":1270198761307,"userstat":1,"status":0,"crdate":1270198761307,"xtype":"S","indexdel":0,"version":0,"id":43,"stats_schema_ver":0,"seltrig":0,"type":"S","name":"sysxsrvs","info":0,"cache":0,"replinfo":0,"updtrig":0,"ftcatid":0,"category":2,"instrig":0}],"Cols":[{"JsonType":"string","FieldIndex":0,"FieldType":"WideString","FieldSize":128,"FieldName":"name","Required":true},{"JsonType":"integer","FieldIndex":1,"FieldType":"Integer","FieldSize":0,"FieldName":"id","Required":true},{"JsonType":"string","FieldIndex":2,"FieldType":"String","FieldSize":2,"FieldName":"xtype","Required":true},{"JsonType":"integer","FieldIndex":3,"FieldType":"Smallint","FieldSize":0,"FieldName":"uid","Required":false},{"JsonType":"integer","FieldIndex":4,"FieldType":"Smallint","FieldSize":0,"FieldName":"info","Required":false},{"JsonType":"integer","FieldIndex":5,"FieldType":"Integer","FieldSize":0,"FieldName":"status","Required":false},{"JsonType":"integer","FieldIndex":6,"FieldType":"Integer","FieldSize":0,"FieldName":"base_schema_ver","Required":false},{"JsonType":"integer","FieldIndex":7,"FieldType":"Integer","FieldSize":0,"FieldName":"replinfo","Required":false},{"JsonType":"integer","FieldIndex":8,"FieldType":"Integer","FieldSize":0,"FieldName":"parent_obj","Required":true},{"JsonType":"variant","FieldIndex":9,"FieldType":"TimeStamp","FieldSize":0,"FieldName":"crdate","Required":true},{"JsonType":"integer","FieldIndex":10,"FieldType":"Smallint","FieldSize":0,"FieldName":"ftcatid","Required":false},{"JsonType":"integer","FieldIndex":11,"FieldType":"Integer","FieldSize":0,"FieldName":"schema_ver","Required":false},{"JsonType":"integer","FieldIndex":12,"FieldType":"Integer","FieldSize":0,"FieldName":"stats_schema_ver","Required":false},{"JsonType":"string","FieldIndex":13,"FieldType":"String","FieldSize":2,"FieldName":"type","Required":false},{"JsonType":"integer","FieldIndex":14,"FieldType":"Smallint","FieldSize":0,"FieldName":"userstat","Required":false},{"JsonType":"integer","FieldIndex":15,"FieldType":"Smallint","FieldSize":0,"FieldName":"sysstat","Required":false},{"JsonType":"integer","FieldIndex":16,"FieldType":"Smallint","FieldSize":0,"FieldName":"indexdel","Required":false},{"JsonType":"variant","FieldIndex":17,"FieldType":"TimeStamp","FieldSize":0,"FieldName":"refdate","Required":true},{"JsonType":"integer","FieldIndex":18,"FieldType":"Integer","FieldSize":0,"FieldName":"version","Required":false},{"JsonType":"integer","FieldIndex":19,"FieldType":"Integer","FieldSize":0,"FieldName":"deltrig","Required":false},{"JsonType":"integer","FieldIndex":20,"FieldType":"Integer","FieldSize":0,"FieldName":"instrig","Required":false},{"JsonType":"integer","FieldIndex":21,"FieldType":"Integer","FieldSize":0,"FieldName":"updtrig","Required":false},{"JsonType":"integer","FieldIndex":22,"FieldType":"Integer","FieldSize":0,"FieldName":"seltrig","Required":false},{"JsonType":"integer","FieldIndex":23,"FieldType":"Integer","FieldSize":0,"FieldName":"category","Required":false},{"JsonType":"integer","FieldIndex":24,"FieldType":"Smallint","FieldSize":0,"FieldName":"cache","Required":false}]}

看到没？Cols和Data的字段顺序是不一致的！Fields是我在循环里面用字符串拼装的（最开始不是这样写的，我以为我手工拼装可以得到预期的顺序，但是因为用了 SO(Fields) 得到JSON

串，所以顺序依然和Cols保持了一致，而这个顺序不是 Select 语句的得到数据集的字段顺序（调试的时候，包括得到的运行时的字符串的内容都和数据集是一致的，但一旦生成为JSON串

以后，顺序就改变了。）。

于是，我决定用QJSON去尝试一下，QJSON得到的结果顺序和我预期是一致的。

代码如下：

 1 class function FDQueryToQJSON(aQuery : TFDQuery) : string;

 2 

 3 class function TFDQueryJSONReflect.FDQueryToQJSON(aQuery: TFDQuery): string;

 4 var

 5   i:Integer;

 6   Fieldtyp,JsonTyp:string;

 7   List:TStringList;

 8   aField : TField;

 9   aqjsonall, aqjson,aqjson2, aqFields, aqjsonTemp : TQJSON;

10 begin

11   aqjsonall := TQJSON.Create;

12   aqjson := aqjsonall.AddArray('Cols');

13   List := TStringList.Create;

14   try

15     List.Sorted := False;

16 

17     aqFields := aqjsonall.AddArray(cstFields);

18 

19     for i := 0 to aQuery.FieldCount - 1 do

20     begin

21       aqjsonTemp := TQJson.Create;

22 

23       GetFieldTypeInfo(aQuery.Fields[i],Fieldtyp,JsonTyp);

24 

25       aqjsonTemp.AddVariant(cstFieldName,aQuery.Fields[i].FieldName);

26       aqjsonTemp.AddVariant(cstFieldType,Fieldtyp);

27       aqjsonTemp.AddVariant(cstJsonType,JsonTyp);

28       aqjsonTemp.AddVariant(cstFieldSize, aQuery.Fields[i].Size);

29       aqjsonTemp.AddVariant(cstRequired, aQuery.Fields[i].Required);

30       aqjsonTemp.AddVariant(cstFieldIndex, aQuery.Fields[i].Index);

31 

32       aqjson.Add(aqjsonTemp);

33       List.Add(aQuery.Fields[i].FieldName+'='+JsonTyp);

34 

35       aqFields.Add.AsString := aQuery.Fields[i].FieldName;

36     end;

37 

38     //创建数据集的数据

39     aQuery.DisableControls;

40     aQuery.First;

41 

42     aqjson2 := aqjsonall.AddArray(cstData);

43 

44     while  not aQuery.Eof do

45     begin

46         aqjsonTemp := aqjson2.AddArray('DataItem');

47       for i := 0 to List.Count - 1 do

48       begin

49         aField := aQuery.Fields.FindField(List.Names[i]);

50 

51         if VarIsNull(aField.Value) then

52           aqjsonTemp.Add.AsString := SO(Null).AsString

53         else

54         begin

55           CreateJsonValueByField(aqjsonTemp,aField);

56         end;

57       end;

58       aQuery.Next;

59     end;

60     Result := aqjsonall.AsString; 61   finally

62     List.Free;

63     aQuery.EnableControls;

64     aqjsonall.Free;

65   end;

66 end;

 

 1 class function CreateJsonValueByField(Json:TQJSON;Field:TField):Boolean; overload;

 2 

 3 class function TFDQueryJSONReflect.CreateJsonValueByField(Json: TQJSON;

 4   Field: TField): Boolean;

 5 begin

 6   Result := False;

 7   if (Field Is TDateTimeField) or (Field is TSQLTimeStampField) then

 8     Json.Add.AsString := FormatdateTime('yyyy-MM-dd hh:mm:ss', Field.AsDateTime)

 9   else if Field is TBlobField then

10     Json.add.AsString := EncodeString(Field.AsString)

11   else

12     Json.Add.AsVariant := Field.Value;

13   Result := True;

14 end;

 

得到的结果如下：

{ "Cols":[ { "FieldName":"name", "FieldType":"WideString", "JsonType":"string", "FieldSize":128, "Required":true, "FieldIndex":0 }, { "FieldName":"id", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":true, "FieldIndex":1 }, { "FieldName":"xtype", "FieldType":"String", "JsonType":"string", "FieldSize":2, "Required":true, "FieldIndex":2 }, { "FieldName":"uid", "FieldType":"Smallint", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":3 }, { "FieldName":"info", "FieldType":"Smallint", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":4 }, { "FieldName":"status", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":5 }, { "FieldName":"base_schema_ver", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":6 }, { "FieldName":"replinfo", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":7 }, { "FieldName":"parent_obj", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":true, "FieldIndex":8 }, { "FieldName":"crdate", "FieldType":"TimeStamp", "JsonType":"variant", "FieldSize":0, "Required":true, "FieldIndex":9 }, { "FieldName":"ftcatid", "FieldType":"Smallint", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":10 }, { "FieldName":"schema_ver", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":11 }, { "FieldName":"stats_schema_ver", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":12 }, { "FieldName":"type", "FieldType":"String", "JsonType":"string", "FieldSize":2, "Required":false, "FieldIndex":13 }, { "FieldName":"userstat", "FieldType":"Smallint", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":14 }, { "FieldName":"sysstat", "FieldType":"Smallint", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":15 }, { "FieldName":"indexdel", "FieldType":"Smallint", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":16 }, { "FieldName":"refdate", "FieldType":"TimeStamp", "JsonType":"variant", "FieldSize":0, "Required":true, "FieldIndex":17 }, { "FieldName":"version", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":18 }, { "FieldName":"deltrig", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":19 }, { "FieldName":"instrig", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":20 }, { "FieldName":"updtrig", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":21 }, { "FieldName":"seltrig", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":22 }, { "FieldName":"category", "FieldType":"Integer", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":23 }, { "FieldName":"cache", "FieldType":"Smallint", "JsonType":"integer", "FieldSize":0, "Required":false, "FieldIndex":24 } ], "Fields":["name","id","xtype","uid","info","status","base_schema_ver","replinfo","parent_obj","crdate","ftcatid","schema_ver","stats_schema_ver","type","userstat","sysstat","indexdel","refdate","version","deltrig","instrig","updtrig","seltrig","category","cache"], "Data":[ ["sysrscols",3,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysrowsets",5,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysallocunits",7,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysfiles1",8,"S",4,0,0,0,0,0,"2003-04-08 09:13:37",0,0,0,"S",1,1,0,"2003-04-08 09:13:37",0,0,0,0,0,2,0], ["syspriorities",17,"S",4,0,0,0,0,0,"2010-04-02 16:59:22",0,0,0,"S",1,1,0,"2010-04-02 16:59:22",0,0,0,0,0,2,0], ["sysdbfrag",18,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysfgfrag",19,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["syspru",21,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysbrickfiles",22,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysphfg",23,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysprufiles",24,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysftinds",25,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysowners",27,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysdbreg",28,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysprivs",29,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysschobjs",34,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["syslogshippers",39,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["syscolpars",41,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysxlgns",42,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0], ["sysxsrvs",43,"S",4,0,0,0,0,0,"2010-04-02 16:59:21",0,0,0,"S",1,1,0,"2010-04-02 16:59:21",0,0,0,0,0,2,0] ] }

可以看到，数据量明显减少，而且并不影响数据的解析。因为Data数组里面的每条记录（也是数组）是和字段信息的顺序一致的。