JsonDataObjects序列和还原

Posted 2020-10-06 咏南中间件和开发框架

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了JsonDataObjects序列和还原相关的知识，希望对你有一定的参考价值。

JsonDataObjects号称DELPHI最快的JSON库，且支持跨平台。

// cxg 2017-9-12
// Use JsonDataObjects(cross platform json library)
// Use delphi 10.2.1

unit ujson;

interface

uses
System.SysUtils, soap.EncdDecd, Web.HTTPApp, System.NetEncoding, Data.DB,
System.Classes, JsonDataObjects;

// {"data":[{"field1":value1,"field2":value2}]};
function datasetToJson(dataset: TDataSet): string;

// {"data":[{"field1":value1,"field2":value2}]};
procedure jsonToDataset(const json: string; dataset: TDataSet);

// {"cols":[{"name":"field1","size":0,"type":"int"}]"data":[{"field1":value1}]};
function datasetToJsonCols(dataset: TDataSet): string;

// {
// "update":[{"table":"表1","where":"字段1=1","字段1":"1","字段2":0}]
// ,"insert":[{"table":"表1","字段1":"1","字段2":0}]
// ,"delete":[{"table":"表1","where":"字段1=1"}]
// };
procedure parseJsonSql(const json: string; outsql: TStrings);

implementation

procedure parseJsonSql(const json: string; outsql: TStrings);
// {
// "update":[{"table":"表1","where":"字段1=1","字段1":"1","字段2":0}]
// ,"insert":[{"table":"表1","字段1":"1","字段2":0}]
// ,"delete":[{"table":"表1","where":"字段1=1"}]
// };
var
obj, childobj: TJsonObject;
tablename, sql, lname, lvalue, where: string;
i, j: Integer;
function _getValue(value: PJsonDataValue): string;
{
TJsonDataType = (
jdtNone, jdtString, jdtInt, jdtLong, jdtULong, jdtFloat, jdtDateTime
, jdtBool, jdtArray, jdtObject
);
}
begin
case Value.Typ of
jdtString: Result := QuotedStr(UTF8ToString(rawbytestring(TNetEncoding.URL.Decode(value.Value)))); // 解码
jdtBool: Result := BoolToStr(value.BoolValue);
jdtFloat: Result := FloatToStr(value.FloatValue);
jdtInt, jdtLong, jdtULong: Result := IntToStr(value.IntValue);
jdtDateTime: Result := DateTimeToStr(value.DateTimeValue);
end;
end;
begin
if outsql = nil then
Exit;
outsql.Clear;
obj := TJsonObject.Parse(json) as TJsonObject;
try
// 解析并生成insert sql begin-----------------------------------
for i := 0 to obj.A[‘insert‘].Count - 1 do
begin
childobj := obj.A[‘insert‘].O[i];
lname := ‘‘;
lvalue := ‘‘;
for j := 0 to childobj.Count - 1 do
begin
if childobj.Names[j] = ‘table‘ then
begin
tablename := childobj.Items[j].Value;
Continue;
end;
if lname = ‘‘ then
lname := childobj.Names[j]
else
lname := lname + ‘,‘ + childobj.Names[j];
if lvalue = ‘‘ then
lvalue := _getValue(childobj.Items[j])
else
lvalue := lvalue + ‘,‘ + _getValue(childobj.Items[j]);
end;
sql := ‘insert into ‘ + tablename + ‘ (‘ + lname + ‘) values (‘ + lvalue + ‘)‘;
outsql.Add(sql);
end;
// 解析并生成insert sql end----------------------------------------
// 解析并生成update sql begin---------------------------------------
for i := 0 to obj.A[‘update‘].Count - 1 do
begin
childobj := obj.A[‘update‘].O[i];
lname := ‘‘;
lvalue := ‘‘;
for j := 0 to childobj.Count - 1 do
begin
if childobj.Names[j] = ‘table‘ then
begin
tablename := childobj.Items[j].Value;
Continue;
end
else
if childobj.Names[j] = ‘where‘ then
begin
where := childobj.Items[j].Value;
Continue;
end;
if lname = ‘‘ then
lname := childobj.Names[j] + ‘=‘ + _getValue(childobj.Items[j])
else
lname := lname + ‘,‘ + childobj.Names[j] + ‘=‘ + _getValue(childobj.Items[j]);
end;
sql := ‘update ‘ + tablename + ‘ set ‘ + lname + ‘ where ‘ + where;
outsql.Add(sql);
end;
// 解析并生成update sql end--------------------------------------------
// 解析并生成delete sql begin--------------------------------------------
for i := 0 to obj.A[‘delete‘].Count - 1 do
begin
childobj := obj.A[‘delete‘].O[i];
lname := ‘‘;
lvalue := ‘‘;
for j := 0 to childobj.Count - 1 do
begin
if childobj.Names[j] = ‘table‘ then
begin
tablename := childobj.Items[j].Value;
Continue;
end
else
if childobj.Names[j] = ‘where‘ then
begin
where := childobj.Items[j].Value;
Continue;
end;
end;
sql := ‘delete from ‘ + tablename + ‘ where ‘ + where;
outsql.Add(sql);
end;
// 解析并生成delete sql end-------------------------------------------
finally
obj.free;
end;
end;

function _getFieldType(fld: TField): string;
begin
case fld.DataType of
ftBoolean:
Result := ‘bool‘;
ftSmallint, ftInteger, ftWord, ftAutoInc:
Result := ‘int‘;
ftLargeint:
Result := ‘int64‘;
ftFloat, ftBCD, ftCurrency:
Result := ‘float‘;
ftTimeStamp, ftDate, ftTime, ftDateTime:
Result := ‘datetime‘;
ftString, ftFixedChar, ftMemo, ftWideString:
Result := ‘string‘;
ftBytes, ftVarBytes, ftBlob, ftGraphic, ftOraBlob, ftOraClob:
Result := ‘blob‘;
end;
end;

begin
// {"cols":[{"name":"c1","size":0,"type":"int"}]"data":[{"c1":1}]};
Result := ‘{"result":"false"}‘;
if (dataset = nil) or (not dataset.Active) then
Exit;
obj := TJsonObject.Create;
obj.A[‘cols‘];
obj.A[‘data‘];
dataset.First;
for i := 0 to dataset.FieldCount - 1 do // fill cols array
begin
field := dataset.Fields[i];
childobj := obj.A[‘cols‘].AddObject;
childobj.S[‘name‘] := field.FieldName;
childobj.I[‘size‘] := field.Size;
childobj.S[‘type‘] := _getFieldType(field);
childobj.B[‘required‘] := field.Required;
childobj.B[‘readonly‘] := field.ReadOnly;
end;
// fill data array
dataset.First;
while not dataset.Eof do
begin
childobj := obj.A[‘data‘].AddObject;
for i := 0 to dataset.FieldCount - 1 do
begin
field := dataset.Fields[i];
if field.IsNull then
childobj.S[field.FieldName] := ‘‘
else
begin
case field.DataType of
ftBoolean:
childobj.B[field.FieldName] := field.AsBoolean;
ftSmallint, ftInteger, ftWord, ftAutoInc:
childobj.I[field.FieldName] := field.AsInteger;
ftLargeint:
childobj.L[field.FieldName] := TLargeintField(field).AsLargeInt;
ftFloat, ftBCD, ftCurrency:
childobj.F[field.FieldName] := field.AsFloat;
ftTimeStamp, ftDate, ftTime, ftDateTime:
childobj.D[field.FieldName] := field.AsDateTime;
ftString, ftFixedChar, ftMemo, ftWideString:
childobj.S[field.FieldName] := TNetEncoding.URL.Encode(string(UTF8Encode(field.AsString))); // 编码
ftBytes, ftVarBytes, ftBlob, ftGraphic, ftOraBlob, ftOraClob:
begin
blob := TStringStream.Create(‘‘);
try
TBlobField(field).SaveToStream(blob);
childobj.S[field.FieldName] := EncodeString(blob.DataString); // base64 编码
finally
blob.Free;
end;
end;
end;
end;
end; // end for
dataset.Next;
end; // end while
Result := obj.ToString;
end;

procedure jsonToDataset(const json: string; dataset: TDataSet);
// {"data":[{"field1":value1,"field2":value2}]};
var
obj, childobj: TJsonObject;
i, j: Integer;
field: TField;
blob: TStringStream;
begin
if (dataset = nil) or (not dataset.Active) or (json = ‘{"result":"false"}‘) then
Exit;
obj := TJsonObject.Parse(json) as TJsonObject;
dataset.DisableControls;
try
for i := 0 to obj.A[‘data‘].Count - 1 do
begin
dataset.Append;
childobj := obj.A[‘data‘].O[i];
if childobj = nil then
continue;
for j := 0 to dataset.FieldCount - 1 do
begin
field := dataset.Fields[j];
if field = nil then
Continue;
case field.datatype of
ftBoolean:
field.AsBoolean := childobj.B[field.FieldName];
ftFloat, ftBCD, ftCurrency:
field.AsFloat := childobj.F[field.FieldName];
ftSmallint, ftInteger, ftWord, ftAutoInc:
field.AsInteger := childobj.I[field.FieldName];
ftString, ftFixedChar, ftMemo, ftWideString:
field.AsString :=UTF8ToString(rawbytestring( TNetEncoding.URL.Decode(childobj.S[field.FieldName]))); // 解码
ftTimeStamp, ftDate, ftTime, ftDateTime:
field.AsDateTime := childobj.D[field.FieldName];
ftLargeint:
TLargeintField(field).AsLargeInt := childobj.L[field.FieldName];
ftBytes, ftVarBytes, ftBlob, ftGraphic, ftOraBlob, ftOraClob:
begin
blob := TStringStream.Create(DecodeString(childobj.S[field.FieldName]));
try
TBlobField(field).LoadFromStream(blob);
finally
blob.Free;
end;
end;
end;
end;
dataset.Post;
end;
finally
dataset.EnableControls;
obj.free;
end;
end;

end.

以上是关于JsonDataObjects序列和还原的主要内容，如果未能解决你的问题，请参考以下文章

优秀的数据序列和还原类----TSimpleMsgPack

结构体的序列和还原（使用Move方法）