怎样实现多个客户端连接服务器，请各位高手帮帮忙！

Question

这是在网上下载的，因为对网络传输文件这方面很菜，请各位高手帮帮忙，急着用，在线等!
先谢谢各位了！
\===============================================================================
procedure Tfrm_Server.IdTCPServer1Execute(AThread: TIdPeerThread);
var
  cmd: string; //接收到客户端的字符串信息
  ASize: Integer;
  count:integer; //需要传输的流大小
begin
  with AThread.Connection do //已经连街上的一个进程
  begin
    cmd := UpperCase(ReadLn); //客户端发送的命令字符串
    if cmd = 'BEGIN' then //开始传输
    begin
      //告诉远程传输文件的大小和文件名
      AFileStream := TFileStream.Create(filelist.Items.Strings[i], fmOpenRead);
      ProgressBar1.Max := AFileStream.Size;
      ProgressBar1.Position := 0;
      WriteLn(Format('%d|%s', [AFileStream.Size, filelist.Items.Strings[i]]));
      StatusBar1.SimpleText := '准备传输...';
      Exit;
    end;
    if cmd = 'END' then
    begin //传输完成
      Button3.Click;
      StatusBar1.SimpleText := '传输完成...';
      Exit;
    end;
    if cmd = 'CANCEL' then
    begin //传输取消
      StatusBar1.SimpleText := '传输取消...';
      //保持传输状态
      Exit;
    end;
    //按照指定位置传输文件
    AFileStream.Seek(StrToInT(cmd), soFromBeginning); //转到文件流传输的位置
    ASize := Min(AFileStream.Size - AFileStream.Position, RecvBufferSize);
    //计算需要发送的大小，Min()函数在Math单元
    OpenWriteBuffer; //准备发送缓冲
    WriteStream(AFileStream, false, false, ASize);
    //注意这个函数的参数。
    CloseWriteBuffer; //结束发送缓冲
    StatusBar1.SimpleText := Format('当前传输位置%s/大小%d', [cmd, AFileStream.Size]);
    ProgressBar1.Position := ProgressBar1.Position + ASize;
  end;
end;
=====================================================================================这个程序我想大家都熟悉，我测试的时候，只能和一个客户端发送，连接多个就行。

Answer 1

try
AThread.Synchronize(IncCon)
finally
AThread.Synchronize(DecCon)
end;

Answer 2

结束后
AThread.Connection.Disconnect

Answer 3

这是服务器端主程序,支持返回数据集,执行SQL语句等 
procedure TfrmDM.tcpSvrExecute(AThread: TIdPeerThread);
var
    APeerIP                   : string;
    APeerPort, iCmd           : Integer;
    iErrorCnt                 : Integer;begin    with AThread.Connection do
    try
        CoInitialize(nil);
        SvrParam.DataStream := TMemoryStream.Create;        CltParam.DataStream := TMemoryStream.Create;        AThread.Synchronize(IncCon);        APeerIP := AThread.Connection.Socket.Binding.PeerIP;
        APeerPort := AThread.Connection.Socket.Binding.PeerPort;        begin
            CltParam.Cmd := ReadInteger();
            CheckCmdPermission(iCmd);
            case CltParam.Cmd of
                0:                                          //TestCon
                    begin
                        SvrParam.iResult := 0;
                        WriteInteger(SvrParam.iResult);
                    end;
                1:                                          //GetData
                    begin
                        with cdsBill do
                        try
                            if Active then
                                Active := False;
                            CltParam.SQL := ReadLn;
                            ShowMessage(CltParam.SQL);
                            CommandText := CltParam.SQL;
                            Active := True;
                            SvrParam.iResult := 0;
                            cdsCommon.SaveToStream(SvrParam.DataStream,dfBinary);
                            WriteInteger(SvrParam.iResult);
                            OpenWriteBuffer();
                            WriteStream(SvrParam.DataStream);
                            CloseWriteBuffer;
                        except
                            on E: Exception do
                            begin
                                SvrParam.Info := '获取数据出错:' + E.Message + #13'语句:' + CltParam.SQL;
                                SvrParam.iResult := -1;
                                Writeln(SvrParam.Info);
                            end;
                        end;
                    end;
                2:                                          //ExecSQL
                    begin
                        with cdsBill do
                        try
                            if Active then
                                Active := False;
                            CommandText := CltParam.SQL;
                            Execute;
                            SvrParam.iResult := 0;
                            WriteInteger(SvrParam.iResult);
                            //WriteBuffer(SvrParam, SizeOf(SvrParam), True);
                        except
                            on E: Exception do
                            begin
                                SvrParam.iResult := -1;
                                SvrParam.Info := '执行语句出错:' + E.Message + #13'语句:' + CltParam.SQL;
                                Writeln(SvrParam.Info);
                            end;
                        end;
                    end;
                3:                                          //提交数据
                    begin
                        with qryBill do
                        try
                            if Active then
                                Active := False;
                            SQL.Text := CltParam.SQL;
                            Active := True;
                            ReadStream(CltParam.DataStream, -1, True);
                            cdsCommon.LoadFromStream(CltParam.DataStream);
                            dspBill.ApplyUpdates(cdsCommon.Data, 0, iErrorCnt);
                        except
                            on E: Exception do
                            begin
                                SvrParam.iResult := -1;
                                SvrParam.Info := '提交数据出错:' + E.Message + #13'语句:' + CltParam.SQL;
                                Writeln(SvrParam.Info);
                            end;
                        end;
                    end;
            end;
        end;
    finally
        try
            SvrParam.DataStream.Free;
            CltParam.DataStream.Free;
            AThread.Connection.Disconnect;
            AThread.Synchronize(DecCon);
            CoUninitialize;
        except        end;    end;
end;

Answer 4

客户端的核心代码
function TfrmDM._ExecSQL(SQL: string): Boolean;
begin
    with tcpClt do
    begin
        _ReConnect;
        WriteInteger(9);
        WriteLn(SQL);
        Result := ReadInteger() = 1;
        if not Result then
            ShowMessage(ReadLn());
        Disconnect;
    end;end;function TfrmDM._GetData(SQL: string): OleVariant;
var
    IsOK                      : Boolean;
begin
    with tcpClt do
    begin
        _ReConnect;
        WriteInteger(10);
        WriteLn(SQL);
        IsOK := ReadInteger() = 1;
        if not IsOK then
            ShowMessage(ReadLn())
        else
        begin
            cdsCommon.Active := False;
            TmpStream := TMemoryStream.Create;
            ReadStream(TmpStream, -1, True);
            TmpStream.Seek(0, soFromBeginning);
            cdsCommon.LoadFromStream(TmpStream);
            Result := cdsCommon.Data;
            //Result := True;
            TmpStream.Free;
        end;
        Disconnect;
    end;
end;

Answer 5

IncCon和DecCon是什么意思？是不是记录连接数？

Answer 6

这是客户端的程序
===============================================================
var
  cmd: string;
  ASize, TotalSize: Int64;
  AFileStream: TFileStream;
  str:string;
  i,count:integer;
begin
  bt_accept.Enabled:=false;
  bt_cancel.Enabled:=true;
  IdTCPClient1.Host := Edit1.Text; //连接主机
  IdTCPClient1.Port := StrToIntDef(Edit2.Text, 9925); //端口
  IdTCPClient1.Connect;//连接
  IdTCPClient1.WriteLn('BEGINA');
  count :=strtoint(IdTCPClient1.ReadLn);
  str:=edit3.Text+'\';
  i:=0;
  try
    repeat  //控制文件个数
    IdTCPClient1.WriteLn('BEGIN'); //提示服务器开始接收
    cmd := IdTCPClient1.ReadLn;
    TotalSize := StrToInt(Copy(cmd, 0, Pos('|', cmd) - 1));
    //建立文件流准备接收
    AFileStream := TFileStream.Create(str+Extractfilename(copy(cmd,pos('|',cmd)+1,length(cmd)-pos('|',cmd))), fmCreate);
    try //循环开始接受
      repeat
        IdTCPClient1.WriteLn(IntToStr(AFileStream.Size));//发送当前传输的位置
        ASize := Min(TotalSize - AFileStream.Size, IdTCPClient1.RecvBufferSize);
        //选择剩余大小和缓冲区大小小的一个作为传输的大小
        IdTCPClient1.ReadStream(AFileStream, ASize,false); //接收流
        StatusBar1.SimpleText := Format('当前传输位置%d/大小%d', [AFileStream.Size, TotalSize]);
        Application.ProcessMessages;
      until AFileStream.Size = TotalSize; //大小一致了表示结束
    finally
      AFileStream.Free; //释放文件流
    end;
    IdTCPClient1.WriteLn('ENDA'); //提示服务器传输完成
    i:=strtoint(IdTCPClient1.ReadLn);
    until i=count;
  except
    StatusBar1.SimpleText := '连接服务器失败或者对方已经中断传输！';
  end;
  IdTCPClient1.WriteLn('END');
  StatusBar1.SimpleText := '传输完成...';
  IdTCPClient1.Disconnect;
  bt_accept.Enabled:=true;
  bt_cancel.Enabled:=false;
end;