delphi中json转dataset

Posted 2022-01-24 zyb2016

unit uJSONDB;

interface
uses
SysUtils, Classes, Variants, DB, DBClient, SuperObject, Dialogs;
type
TJSONDB = class

private
class function getJsonFieldNames(res: ISuperObject):TStringList ;
class function getJsonFieldValues(res: ISuperObject):TStringList ;
public
class procedure JsonToClientDataSet(jsonArr: TSuperArray; dstCDS: TClientDataSet);
//class procedure JsonToClientDataSetF(jsonArr: TSuperArray; dstCDS: TClientDataSet;fs:String);
class function ClientDataSetToJSON(srcCDS: TClientDataSet):UTF8String;
end;
//type
// TArrayDim = Array of ShortString;

implementation

function GetToken(var astring: string;const fmt:array of char): string;
var
i,j:integer;
Found:Boolean;
begin
found:=false;
result:=‘‘;
aString := TrimLeft(aString);

if length(astring)=0 then exit;

I:=1;
while I<=length(Astring) do
begin
found:=false;
if aString[i]<=#128 then
begin
for j:=Low(Fmt) to High(Fmt) do
begin
if (astring[i]<>Fmt[j]) then continue;
found:=true;
break;
end;
if Not found then I:=I+1;
end
else I:=I+2;

if found then break;
end;

if found then
begin
result:=copy(astring,1,i-1);
delete(astring,1,i);
end
else
begin
result:=astring;
astring:=‘‘;
end;
end;

function GetFieldParams(PropName, Source:string): string;
var
S1, S2: string;
TmpParam: string;
AChar: string;
aValue, aPropName, aSource: string;
begin
Result:=‘‘;
if Source=‘‘ then Exit;
aSource := Source;
while aSource <> ‘‘ do
begin
aValue := GetToken(aSource,[‘,‘]);
aPropName := GetToken(aValue,[‘:‘]);
if CompareText(PropName,aPropName) <> 0 then continue;
Result := aValue;
break;
end;
end;
//從json取得欄位名稱
class function TJSONDB.getJsonFieldNames(res: ISuperObject):TStringList ;
var
i: Integer;
fieldList : TStringList;
fieldNames :String;

begin
try
fieldList := TStringList.Create;
fieldNames := res.AsObject.getNames.AsString;

fieldNames := StringReplace(fieldNames, ‘[‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);
fieldNames := StringReplace(fieldNames, ‘]‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);
fieldNames := StringReplace(fieldNames, ‘"‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);

fieldList.Delimiter := ‘,‘;
fieldList.DelimitedText := fieldNames;
Result:= fieldList;
finally
//fieldList.Free;
end;
end;

//從json取得欄位值
class function TJSONDB.getJsonFieldValues(res: ISuperObject):TStringList ;
var
i: Integer;
fieldList : TStringList;
fieldValues :String;
begin
try
fieldList := TStringList.Create;
fieldValues := res.AsObject.getValues.AsString;
fieldValues := StringReplace(fieldValues, ‘[‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);
fieldValues := StringReplace(fieldValues, ‘]‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);
fieldValues := StringReplace(fieldValues, ‘"‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);

fieldList.Delimiter := ‘,‘;
fieldList.DelimitedText := fieldValues;
Result:= fieldList;
finally
//fieldList.Free;
end;
end;
//json轉CDS
class procedure TJSONDB.JsonToClientDataSet(jsonArr: TSuperArray; dstCDS: TClientDataSet);
var
fieldList: TStringList;
valuesList: TStringList;
jsonSrc: string;
i, j: Integer;
jo: ISuperObject;

jts: TSuperTableString;
ja: TSuperArray;

iter: TSuperObjectIter;
ss,s1:String;
dps:TSupertype;
ft:TFieldType;
len:integer;
// XJSon :TlkJSONobject;
begin

fieldList:= getJsonFieldNames(SO[jsonArr[0].AsJson(False,False)]);
if (dstCDS.FieldCount = 0) then
begin
jo:= so(jsonArr[0].AsString);
// iter:=jo.AsObject.GetEnumerator;
// xjson:= TlkJSON.ParseText(jsonArr[0]);
for i := 0 to fieldList.Count -1 do
begin

if ObjectFindFirst(jo, iter) then
begin
repeat
dps:=iter.Ite.Current.Value.DataType;
ss:=iter.Ite.Current.Name;
if trim(ss)= trim(fieldList[i]) then
break;
until not ObjectFindNext(iter);
end;
ObjectFindClose(iter);
ft := ftString;
case dps of
stNull: ft := ftString;
stBoolean: ft := ftString;
stDouble: ft := ftFloat;
stCurrency: ft := ftFloat;
stInt: ft := ftFloat;
stString: ft := ftString;
end;
if (ft=ftFloat) then
begin
dstCDS.FieldDefs.Add(fieldList[i],ft);
// s1:=s1+fieldList[i]+‘,‘;
end;
if (ft=ftString) then
begin
len:=100; //默认字段长度为100
s1:=copy(fieldList[i],1,3);//判断是否属于需要特殊设置长度的字段
if s1=‘AAA‘ then //根据设置的特殊字段名称AAA开始的字段，_开始后面的数字为字段长度
begin
len:=pos(‘_‘,fieldList[i]) ;
len:=strtointdef(copy(fieldList[i],len+1,length(fieldList[i])-len),100); //获取特殊字段的长度设置
end;
dstCDS.FieldDefs.Add(fieldList[i],ft,len,false); // ftVarBytes ftString
end;
end;
dstCDS.CreateDataSet;
dstCDS.Close;
dstCDS.Open;
end;
try
dstCDS.DisableControls;
for i := 0 to jsonArr.Length -1 do
begin

jts:=jsonArr[i].AsObject;
ja:=jts.GetValues.AsArray;

// jsonSrc:= SO[jsonArr[i].AsJson(False,False)].AsString;
// jsonSrc := StringReplace(jsonSrc, ‘[‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);
// jsonSrc := StringReplace(jsonSrc, ‘]‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);
// jsonSrc := StringReplace(jsonSrc, ‘"‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);
// jsonSrc := StringReplace(jsonSrc, ‘‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);
// jsonSrc := StringReplace(jsonSrc, ‘‘, ‘‘, [rfReplaceAll, rfIgnoreCase]);

dstCDS.Append;
for j:= 0 to fieldList.Count -1 do
begin
ss:= GetFieldParams(fieldList[j], jsonSrc);

ss:=ja[j].AsString;
if trim(ss)=‘null‘ then
ss:=‘‘;
dstCDS.FieldByName(fieldList[j]).AsString:=ss;
end;
dstCDS.Post;
end;

finally
dstCDS.EnableControls;
end;
end;

//ClientDataSet轉JSON
class function TJSONDB.ClientDataSetToJSON(srcCDS: TClientDataSet): UTF8String;
var
i, j: Integer;
keyValue:String;
jsonList:TStringList;
jsonResult:String;
begin
if not srcCDS.Active then srcCDS.Open;

try
jsonList := TStringList.Create;
srcCDS.DisableControls;
srcCDS.First;
while not srcCDS.Eof do
begin
keyValue:= ‘‘;
for i := 0 to srcCDS.FieldDefs.Count -1 do
begin
keyValue:= keyValue + Format(‘"%s":"%s",‘,[srcCDS.Fields[i].FieldName, srcCDS.Fields[i].AsString]);

end;
jsonList.Add(Format(‘%s‘,[Copy(keyValue, 0, Length(keyValue)-1)]));
srcCDS.Next;
end;
for i := 0 to jsonList.Count -1 do
begin
jsonResult := jsonResult + jsonList[i] + ‘,‘;
end;
Result:= Utf8Encode(Format(‘[%s]‘, [Copy(jsonResult, 0, Length(jsonResult)-1)]));
finally
srcCDS.EnableControls;
jsonList.Free;
end;
end;



end.