小贝子编程

仅从JSON数组中获取第一个值.我该怎么办



※请理解我英语不好，所以我用翻译提问。※

您希望导入并使用JSON数组中的所有值。

然而，我在编写代码后完成了加载，但似乎只有第一个或最后一个值出现。添加了数组编号并尝试了所有操作，但没有收到任何值或出现错误。

在堆栈溢出中找到并使用了在JSON数组中获取值的代码：Delphi解析JSON数组或数组

JSON代码与我的有点不同，但我对它进行了一些修改，它运行得很好。然而，我之所以询问专家，是因为只提出第一个或最后一个值是荒谬的。

//============JSON CODE===============
[
{
"VehicleWeight": "3.5톤",
"AlightArea": "경남 창원시 성산구 남산동",
"Fee_Driver": "70000",
"LoadArea": "경남 함안군 산인면",
"Commission": "0",
"LiveTime": "2022-08-19 09:39:05",
"AlightDate": "2022-08-19",
"LoadDate": "2022-08-19",
"GoodName": "",
"ActionName": "취소",
"VehicleType": "카고",
"sk": "data#",
"OrderCondition": "3",
"Transport_ID": "B2682B5FC09C4CE38F2F14C84C4829D1",
"pk": "B2682B5FC09C4CE38F2F14C84C4829D1#owner",
"MultiLoading": "0",
"Shipper_Name": "한국거성화물(주)"
},
{
"VehicleWeight": "5톤축",
"AlightArea": "경남 함안군 칠서면",
"Fee_Driver": "130000",
"LoadArea": "경남 창원시 진해구 가주동",
"Commission": "0",
"LiveTime": "2022-08-19 09:00:00",
"AlightDate": "2022-08-19",
"LoadDate": "2022-08-19",
"GoodName": "목재",
"ActionName": "취소",
"VehicleType": "카고",
"sk": "data#",
"OrderCondition": "3",
"Transport_ID": "AB8D6C1ABA30497E95BD6FFF287E47A5",
"pk": "AB8D6C1ABA30497E95BD6FFF287E47A5#owner",
"MultiLoading": "0",
"Shipper_Name": "한국거성화물(주)"
},
{
"VehicleWeight": "2.5톤",
"AlightArea": "대구 달성군 유가읍",
"Fee_Driver": "90000",
"LoadArea": "경남 함안군 대산면",
"Commission": "0",
"LiveTime": "2022-08-19 11:06:24",
"AlightDate": "2022-08-19",
"LoadDate": "2022-08-19",
"GoodName": "",
"ActionName": "취소",
"VehicleType": "카고",
"sk": "data#",
"OrderCondition": "3",
"Transport_ID": "F103B2FC1A8B42C9BCB350A8041BCEA4",
"pk": "F103B2FC1A8B42C9BCB350A8041BCEA4#owner",
"MultiLoading": "0",
"Shipper_Name": "한국거성화물(주)"
},
{
"VehicleWeight": "5톤",
"AlightArea": "경남 밀양시 부북면",
"Fee_Driver": "120000",
"LoadArea": "경남 창원시 의창구 대원동",
"Commission": "0",
"LiveTime": "2022-08-19 09:00:00",
"AlightDate": "2022-08-19",
"LoadDate": "2022-08-19",
"GoodName": "",
"ActionName": "취소",
"VehicleType": "윙바디",
"sk": "data#",
"OrderCondition": "3",
"Transport_ID": "C468AAC449B343CB8CB3349CD9FD46A7",
"pk": "C468AAC449B343CB8CB3349CD9FD46A7#owner",
"MultiLoading": "0",
"Shipper_Name": "한국거성화물(주)"
},
{
"VehicleWeight": "5톤",
"AlightArea": "대전 대덕구",
"Fee_Driver": "220000",
"LoadArea": "경남 함안군 대산면",
"Commission": "0",
"LiveTime": "2022-08-19 10:03:16",
"AlightDate": "2022-08-19",
"LoadDate": "2022-08-19",
"GoodName": "",
"ActionName": "취소",
"VehicleType": "카고",
"sk": "data#",
"OrderCondition": "3",
"Transport_ID": "A89FE76963374084933E89C3BD4CB57C",
"pk": "A89FE76963374084933E89C3BD4CB57C#owner",
"MultiLoading": "0",
"Shipper_Name": "한국거성화물(주)"
},
{
"VehicleWeight": "5톤",
"AlightArea": "경북 칠곡군 약목면",
"Fee_Driver": "120000",
"LoadArea": "경북 영천시 북안면",
"Commission": "0",
"LiveTime": "2022-08-19 09:46:20",
"AlightDate": "2022-08-19",
"LoadDate": "2022-08-19",
"GoodName": "7.5미터",
"ActionName": "취소",
"VehicleType": "윙바디",
"sk": "data#",
"OrderCondition": "3",
"Transport_ID": "846A5E797D9E4A8097D816C83FE0034E",
"pk": "846A5E797D9E4A8097D816C83FE0034E#owner",
"MultiLoading": "0",
"Shipper_Name": "한국거성화물(주)"
},
{
"VehicleWeight": "5톤",
"AlightArea": "경기 화성시 서신면",
"Fee_Driver": "110000",
"LoadArea": "충남 아산시 둔포면",
"Commission": "0",
"LiveTime": "2022-08-19 11:00:00",
"AlightDate": "2022-08-19",
"LoadDate": "2022-08-19",
"GoodName": "",
"ActionName": "등록",
"VehicleType": "카고/윙바디",
"sk": "data#",
"OrderCondition": "1",
"Transport_ID": "780F2633C16542809FBB96ADADFFBA35",
"pk": "780F2633C16542809FBB96ADADFFBA35#owner",
"MultiLoading": "0",
"Shipper_Name": "한국거성화물(주)"
}
]

unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls, IdSSL , IdSSLOpenSSL, HTTPApp , IdURI,
IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient, IdHTTP, System.JSON,
Vcl.Grids, Data.DB, Vcl.DBGrids;
type
TForm1 = class(TForm)
DateTimePicker1: TDateTimePicker;
Edit1: TEdit;
Button1: TButton;
IdHTTP1: TIdHTTP;
StringGrid1: TStringGrid;
editPK: TEdit;
Memo1: TMemo;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure StringGrid1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
{Automatic column size adjustment}
procedure AutoSizeGridColumn(Grid : TStringGrid; column : integer);
var
i : integer;
temp : integer;
max : integer;
begin
max := 0;
for i := 0 to (Grid.RowCount-1) do
begin
// Among the width of each row in the specified column based on Grid Canvas
// The maximum value is determined by the width of the column
temp := Grid.Canvas.TextWidth(grid.cells[column, i]);
if temp > max then
max := temp;
end;
Grid.ColWidths[column] := max + Grid.GridLineWidth + 20;
end;
{End of autosize Column}
//*************************************************************
//==========================Get JSON array values=========================
function getData(JsonString: String; User: String; Field: String): String;
var
JSonValue: TJSonValue;
JsonArray: TJSONArray;
ArrayElement: TJSonValue;
FoundValue: TJSonValue;
begin
Result :='';
// create TJSonObject from string
JsonValue := TJSonObject.ParseJSONValue(JsonString);
// get the array
JsonArray := JsonValue as TJSONArray;
// iterate the array
for ArrayElement in JsonArray do begin
FoundValue := ArrayElement.FindValue(User);
if FoundValue <> nil then begin
Result := ArrayElement.GetValue<string>(Field);
break;
end;
end;
end;
//==========================End of getting JSON array values=========================
procedure TForm1.Button1Click(Sender: TObject);
var
idhttps: TIdHTTP;
sslIOHandler : TIdSSLIOHandlerSocketOpenSSL;
lStream : TStringStream;
JSONValue : TJSONValue;
JSONArray : TJSONArray;
JSONObject, JSONdata: TJSONObject;
JSONCount: integer;
RESULT : String;
ArrayElement: TJSonValue;
FoundValue: TJSonValue;
i : integer;
begin
Try
Result := '';
idhttps := TIdHTTP.Create();
lStream := TStringStream.Create(nil);
sslIOHandler := TIdSSLIOHandlerSocketOpenSSL.Create(nil);
Try
sslIOHandler.SSLOptions.Method := sslvSSLv23;
sslIOHandler.SSLOptions.Mode := sslmClient;
idhttps.IOHandler := sslIOHandler;
// idhttps.Request.CustomHeaders.Add(pAuthorization);
idhttps.HandleRedirects :=False;
idhttps.Request.Method := 'GET';
idhttps.Response.ContentType := 'application/json; charset=utf-8';
idhttps.ConnectTimeout := 10000;
idhttps.ReadTimeout := 10000;
lStream.Position := 0;
idhttps.Get('insert JSON URL', lStream, []);
Finally
Result := TEncoding.UTF8.GetString(lStream.Bytes,0, lStream.Size);
JsonArray := TJSONObject.ParseJSONValue(Result) as TJSONArray;
JSONCount := JsonArray.Count;
StringGrid1.RowCount := JSONCount+1;
for i := 0 to (jsonCount)-1 do
for ArrayElement in JsonArray do begin
StringGrid1.Cells[00,i+1] := getdata(Result, '', 'ActionName');//Status
StringGrid1.Cells[02,i+1] := getdata(Result, '', 'Shipper_Name');//Company Name
StringGrid1.Cells[03,i+1] := getdata(Result, '', 'LoadDate');//Different day
StringGrid1.Cells[04,i+1] := getdata(Result, '', 'LoadArea');//to take over
StringGrid1.Cells[05,i+1] := getdata(Result, '', 'AlightArea');//Downloading
StringGrid1.Cells[06,i+1] := getdata(Result, '', 'AlightDate');//Departure Day
StringGrid1.Cells[07,i+1] := getdata(Result, '', 'VehicleType');//model
StringGrid1.Cells[08,i+1] := getdata(Result, '', 'VehicleWeight');// tonnage
StringGrid1.Cells[09,i+1] := getdata(Result, '', 'GoodName');//Cargo information
StringGrid1.Cells[10,i+1] := getdata(Result, '', 'Fee_Driver');//vehicle freight
StringGrid1.Cells[11,i+1] := getdata(Result, '', 'Commission');//commission
StringGrid1.Cells[12,i+1] := getdata(Result, '', 'sk');//pk
StringGrid1.Cells[13,i+1] := getdata(Result, '', 'pk');//sk
{if StringGrid1.Cells[13,i+1] = '300016244318#9977' then
begin
StringGrid1.Cells[01,i+1] := 'O'//연동화물
end
else
begin
StringGrid1.Cells[01,i+1] := '';//연동화물
end;   }
end;
{StringGrid1 Auto-Size Cell}
for i := 0 to StringGrid1.ColCount-1 do
begin
AutoSizeGridColumn(StringGrid1, i);
end;
{StringGrid1 Auto-Size Cell END}
FreeAndNil(lStream);
FreeAndNil(idhttps);
FreeAndNil(sslIOHandler);
End;
except
on E: EIdHTTPProtocolException do
begin
Result := e.ErrorMessage;
FreeAndNil(idhttps);
FreeAndNil(sslIOHandler);
end;
End;
end;
end.

我在这段代码中看到了很多问题。

在Button1Click()中，外部for循环是不必要的，应该被移除。在两个for循环之间，您正在一次又一次不必要地重新循环通过同一个数组。内部for..in循环就足够了。

此外，让getValue()将原始JSON作为字符串是没有意义的，因为Button1Click()已经解析了它，只是让getValue()一次又一次地重新解析它。浪费了大量的开销。您应该将现有的TJSONArray甚至ArrayElement传递给getValue()(或者更好的做法是，完全消除getValue()，并将其逻辑直接移动到Button1Click，特别是因为您对FindValue(User)的调用没有意义，因为User总是空的(。

此外，getData()和Button1Click()都在泄漏ParseJSONValue()返回的TJSONValue对象。

此外，您应该使用TIdHTTP.Get()的重载，该重载返回string，而不是填充TStream。

此外，您的try..finally需要一些清理，您没有充分保护所有对象不受错误的影响。

话虽如此，不如试试这样的东西：

unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls, IdSSL , IdSSLOpenSSL, HTTPApp , IdURI,
IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient, IdHTTP, System.JSON,
Vcl.Grids, Data.DB, Vcl.DBGrids;
type
TForm1 = class(TForm)
DateTimePicker1: TDateTimePicker;
Edit1: TEdit;
Button1: TButton;
IdHTTP1: TIdHTTP;
StringGrid1: TStringGrid;
editPK: TEdit;
Memo1: TMemo;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure StringGrid1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
{Automatic column size adjustment}
procedure AutoSizeGridColumn(Grid : TStringGrid; Column : integer);
var
i : integer;
temp : integer;
max : integer;
begin
max := 0;
for i := 0 to Grid.RowCount-1 do
begin
// Among the width of each row in the specified column based on Grid Canvas
// The maximum value is determined by the width of the column
temp := Grid.Canvas.TextWidth(Grid.Cells[Column, i]);
if temp > max then
max := temp;
end;
Grid.ColWidths[Column] := max + Grid.GridLineWidth + 20;
end;
{End of autosize Column}
//*************************************************************
procedure TForm1.Button1Click(Sender: TObject);
var
idhttps: TIdHTTP;
sslIOHandler : TIdSSLIOHandlerSocketOpenSSL;
JSONValue : TJSONValue;
JSONArray : TJSONArray;
ArrayElement: TJSONValue;
i : integer;
begin
idhttps := TIdHTTP.Create;
try
sslIOHandler := TIdSSLIOHandlerSocketOpenSSL.Create(idhttps);
sslIOHandler.SSLOptions.Mode := sslmClient;
sslIOHandler.SSLOptions.Method := sslvSSLv23;
idhttps.IOHandler := sslIOHandler;
// idhttps.Request.CustomHeaders.Add(pAuthorization);
idhttps.HandleRedirects := False;
idhttps.ConnectTimeout := 10000;
idhttps.ReadTimeout := 10000;
idhttps.HTTPOptions := idhttps.HTTPOptions + [hoNoProtocolErrorException, hoWantProtocolErrorContent];
Result := idhttps.Get('insert JSON URL');
finally
idhttps.Free;
end;
JSONValue := TJSONObject.ParseJSONValue(Result);
try
JsonArray := JSONValue as TJSONArray;
StringGrid1.RowCount := JsonArray.Count + 1;
i := 1;
for ArrayElement in JsonArray do
begin
StringGrid1.Cells[00,i] := ArrayElement.GetValue<string>('ActionName','');//Status
StringGrid1.Cells[02,i] := ArrayElement.GetValue<string>('Shipper_Name','');//Company Name
StringGrid1.Cells[03,i] := ArrayElement.GetValue<string>('LoadDate','');//Different day
StringGrid1.Cells[04,i] := ArrayElement.GetValue<string>('LoadArea','');//to take over
StringGrid1.Cells[05,i] := ArrayElement.GetValue<string>('AlightArea','');//Downloading
StringGrid1.Cells[06,i] := ArrayElement.GetValue<string>('AlightDate','');//Departure Day
StringGrid1.Cells[07,i] := ArrayElement.GetValue<string>('VehicleType','');//model
StringGrid1.Cells[08,i] := ArrayElement.GetValue<string>('VehicleWeight','');// tonnage
StringGrid1.Cells[09,i] := ArrayElement.GetValue<string>('GoodName','');//Cargo information
StringGrid1.Cells[10,i] := ArrayElement.GetValue<string>('Fee_Driver','');//vehicle freight
StringGrid1.Cells[11,i] := ArrayElement.GetValue<string>('Commission','');//commission
StringGrid1.Cells[12,i] := ArrayElement.GetValue<string>('sk','');//pk
StringGrid1.Cells[13,i] := ArrayElement.GetValue<string>('pk','');//sk
{if StringGrid1.Cells[13,i] = '300016244318#9977' then
begin
StringGrid1.Cells[01,i] := 'O'//연동화물
end else begin
StringGrid1.Cells[01,i] := '';//연동화물
end;}

Inc(i);
end;
finally
JSONValue.Free;
end;
{StringGrid1 Auto-Size Cell}
for i := 0 to StringGrid1.ColCount-1 do
begin
AutoSizeGridColumn(StringGrid1, i);
end;
{StringGrid1 Auto-Size Cell END}
end;
end.

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