引用 Httpapp單元，
使用Httpdecode函數進行解碼

procedure TFrmMain.HTTPServerCommandGet(AThread: TIdPeerThread;
  ARequestInfo: TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);
var
  RespStr,recvText: string;
  msgText: string;
begin
  CoInitialize(nil);
  try
    try
      msgText := ‘Log|【‘+FormatDateTime(‘
 
yyyy-mm-dd hh:mm:ss‘,Now)+‘】‘+Format(‘收到請求:類型:%s, 路徑:%s,來自:%s:%d‘,
                             [ARequestInfo.Command, ARequestInfo.Document,
                             TIdIOHandlerSocket(AThread.Connection.IOHandler).Binding.PeerIP,
                             TIdIOHandlerSocket(AThread.Connection.IOHandler).Binding.PeerPort]);

      SendMessage(FrmMain.Handle,MYTHREAD_MESSAGE,Integer(@msgText),
 
1);
      if ARequestInfo.Command = ‘GET‘ then
        recvText := Utf8ToAnsi(Httpdecode(ARequestInfo.QueryParams))   //引用 Httpapp
      else if ARequestInfo.Command = ‘POST‘ then//post
        recvText := Utf8ToAnsi(ARequestInfo.FormParams);
if (Pos(LowerCase(‘/api/getBusinessHallStatus‘), LowerCase(ARequestInfo.Document)) = 1
 
) then //查詢營業廳狀態接口
      begin
        RespStr := Httpserver_getBusinessHallStatus(recvText);
      end
      begin
        RespStr := ‘URL路徑未定義‘;
      end;
      AResponseInfo.ContentType := ‘text/HTML;charset=utf-8‘;
      AResponseInfo.ContentText := AnsiToUtf8(RespStr);except
      on e: Exception do
      begin
        msgText := ‘ErrorLog|【‘+FormatDateTime(‘yyyy-mm-dd hh:mm:ss‘,Now)+‘】執行HTTPServerCommandGet發生異常，原因：：‘+e.Message;
        SendMessage(FrmMain.Handle,MYTHREAD_MESSAGE,Integer(@msgText),1);
      end;
    end;
  finally
    CoUninitialize;
  end;
end;

Delphi idHttpServer接收Http Get請求解碼問題