筆者在工作中遇到對局域網中各工作站與服務器之間進行Socket通信的問題�，F在將本人總結出來的TServerSocket和TClientSocket兩個組件的基本用法寫出來，希望與您分享。
ClientSocket組件為客戶端組件。它是通信的請求方，也就是說，它是主動地與服務器端建立連接。
ServerSocket組件為服務器端組件。它是通信的響應方，也就是說，它的動作是監聽以及被動接受客戶端的連接請求，并對請求進行回復。
ServerSocket組件可以同時接受一個或多個ClientSocket組件的連接請求，并與每個ClientSocket組件建立單獨的連接，進行單獨的通信。因此，一個服務器端可以為多個客戶端服務。
設計思路
本例包括一個服務器端程序和一個客戶端程序�？蛻舳顺绦蚩梢苑诺蕉鄠�計算機上運行，同時與服務器端進行連接通信。
本例的重點，一是演示客戶端與服務器端如何通信；二是當有多個客戶端同時連接到服務器端時，服務器端如何識別每個客戶端，并對請求給出相應的回復。為了保證一個客戶端斷開連接時不影響其它客戶端與服務器端的通信，同時保證服務器端能夠正確回復客戶端的請求，在本例中聲明了一個記錄類型：
type
client_record=record
CHandle: integer; //客戶端套接字句柄
CSocket:TCustomWinSocket; //客戶端套接字
CName:string; //客戶端計算機名稱
CAddress:string; //客戶端計算機IP地址
CUsed: boolean; //客戶端聯機標志
end;
利用這個記錄類型數據保存客戶端的信息，同時保存當前客戶端的連接狀態。其中，CHandle保存客戶端套接字句柄，以便準確定位每個與服務器端保持連接的客戶端；Csocket保存客戶端套接字，通過它可以對客戶端進行回復。Cused記錄當前客戶端是否與服務器端保持連接。
下面對組件ServerSocket和ClientSocket的屬性設置簡單說明。
ServerSocket的屬性：
· Port，是通信的端口，必須設置。在本例中設置為1025；
· ServerTypt，服務器端讀寫信息類型，設置為stNonBlocking表示異步讀寫信息，本例中采用這種方式。
· ThreadCacheSize，客戶端的最大連接數，就是服務器端最多允許多少客戶端同時連接。本例采用默認值10。
其它屬性采用默認設置即可。
ClientSocket的屬性：
· Port，是通信的端口，必須與服務器端的設置相同。在本例中設置為1025；
· ClientType，客戶端讀寫信息類型，應該與服務器端的設置相同，為stNonBlocking表示異步讀寫信息。
· Host，客戶端要連接的服務器的IP地址。必須設置，當然也可以在代碼中動態設置。
其它屬性采用默認設置即可。
程序源代碼:
· 服務器端源碼（uServerMain.pas）：
unit uServerMain;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ScktComp, ToolWin, ComCtrls, ExtCtrls, StdCtrls, Buttons;
const
CMax=10; //客戶端最大連接數
type
client_record=record
CHandle: integer; //客戶端套接字句柄
CSocket:TCustomWinSocket; //客戶端套接字
CName:string; //客戶端計算機名稱
CAddress:string; //客戶端計算機IP地址
CUsed: boolean; //客戶端聯機標志
end;
type
TfrmServerMain = class(TForm)
ServerSocket: TServerSocket;
ControlBar1: TControlBar;
ToolBar1: TToolBar;
tbConnect: TToolButton;
tbClose: TToolButton;
tbDisconnected: TToolButton;
Edit1: TEdit;
Memo1: TMemo;
StatusBar: TStatusBar;
procedure tbConnectClick(Sender: TObject);
procedure tbDisconnectedClick(Sender: TObject);
procedure ServerSocketClientRead(Sender: TObject;
Socket: TCustomWinSocket);
procedure ServerSocketListen(Sender: TObject;
Socket: TCustomWinSocket);
procedure ServerSocketClientConnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ServerSocketClientDisconnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure tbCloseClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure ServerSocketGetSocket(Sender: TObject; Socket: Integer;
var ClientSocket: TServerClientWinSocket);
procedure ServerSocketClientError(Sender: TObject;
Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
var ErrorCode: Integer);
private
{ Private declarations }
public
{ Public declarations }
session: array[0..CMax] of client_record; //客戶端連接數組
Sessions: integer; //客戶端連接數
end;
var
frmServerMain: TfrmServerMain;
implementation
{$R *.DFM}
//打開套接字連接，并使套接字進入監聽狀態
procedure TfrmServerMain.tbConnectClick(Sender: TObject);
begin
ServerSocket.Open ;
end;
//關閉套接字連接，不再監聽客戶端的請求
procedure TfrmServerMain.tbDisconnectedClick(Sender: TObject);
begin
ServerSocket.Close;
StatusBar.Panels[0].Text :='服務器套接字連接已經關閉，無法接受客戶端的連接請求.';
end;
//從客戶端讀取信息
procedure TfrmServerMain.ServerSocketClientRead(Sender: TObject;
Socket: TCustomWinSocket);
var
i:integer;
begin
//將從客戶端讀取的信息添加到Memo1中
Memo1.Lines.Add(Socket.ReceiveText);
for i:=0 to sessions do
begin
//取得匹配的客戶端
if session[i].CHandle = Socket.SocketHandle then
begin
session[i].CSocket.SendText('回復客戶端'+session[i].CAddress+' ==> '+Edit1.Text);
end;
end;
end;
//服務器端套接字進入監聽狀態，以便監聽客戶端的連接
procedure TfrmServerMain.ServerSocketListen(Sender: TObject;
Socket: TCustomWinSocket);
begin
StatusBar.Panels[0].Text :='等待客戶端連接...';
end;
//當客戶端連接到服務器端以后
procedure TfrmServerMain.ServerSocketClientConnect(Sender: TObject;
Socket: TCustomWinSocket);
var
i,j:integer;
begin
j:=-1;
for i:=0 to sessions do
begin
//在原有的客戶端連接數組中有中斷的客戶端連接
if not session[i].CUsed then
begin
session[i].CHandle := Socket.SocketHandle ;//客戶端套接字句柄
session[i].CSocket := Socket; //客戶端套接字
session[i].CName := Socket.RemoteHost ; //客戶端計算機名稱
session[i].CAddress := Socket.RemoteAddress ;//客戶端計算機IP
session[i].CUsed := True; //連接數組當前位置已經占用
Break;
end;
j:=i;
end;
if j=sessions then
begin
inc(sessions);
session[j].CHandle := Socket.SocketHandle ;
session[j].CSocket := Socket;
session[j].CName := Socket.RemoteHost ;
session[j].CAddress := Socket.RemoteAddress ;
session[j].CUsed := True;
end;
StatusBar.Panels[0].Text := '客戶端 '+Socket.RemoteHost + ' 已經連接';
end;
//當客戶端斷開連接時
procedure TfrmServerMain.ServerSocketClientDisconnect(Sender: TObject;
Socket: TCustomWinSocket);
var
i:integer;
begin
for i:=0 to sessions do
begin
if session[i].CHandle =Socket.SocketHandle then
begin
session[i].CHandle :=0;
session[i].CUsed := False;
Break;
end;
end;
StatusBar.Panels[0].Text :='客戶端 '+Socket.RemoteHost + ' 已經斷開';
end;
//關閉窗口
procedure TfrmServerMain.tbCloseClick(Sender: TObject);
begin
Close;
end;
procedure TfrmServerMain.FormCreate(Sender: TObject);
begin
sessions := 0;
end;
procedure TfrmServerMain.FormClose(Sender: TObject;
var Action: TCloseAction);
begin
ServerSocket.Close ;
end;
//當客戶端正在與服務器端連接時
procedure TfrmServerMain.ServerSocketGetSocket(Sender: TObject;
Socket: Integer; var ClientSocket: TServerClientWinSocket);
begin
StatusBar.Panels[0].Text :='客戶端正在連接...';
end;
//客戶端發生錯誤
procedure TfrmServerMain.ServerSocketClientError(Sender: TObject;
Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
var ErrorCode: Integer);
begin
StatusBar.Panels[0].Text :='客戶端'+Socket.RemoteHost +'發生錯誤！';
ErrorCode := 0;
end;
end.
· 客戶端源碼(uClientMain.pas)：
unit uClientMain;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ScktComp, ComCtrls, ToolWin, ExtCtrls, StdCtrls, Buttons;
const
SocketHost = '172.16.1.6'; //服務器端地址
type
TfrmClientMain = class(TForm)
ControlBar1: TControlBar;
ToolBar1: TToolBar;
tbConnected: TToolButton;
tbSend: TToolButton;
tbClose: TToolButton;
tbDisconnected: TToolButton;
ClientSocket: TClientSocket;
Edit1: TEdit;
Memo1: TMemo;
StatusBar: TStatusBar;
btnSend: TBitBtn;
procedure tbConnectedClick(Sender: TObject);
procedure tbDisconnectedClick(Sender: TObject);
procedure ClientSocketRead(Sender: TObject; Socket: TCustomWinSocket);
procedure tbSendClick(Sender: TObject);
procedure tbCloseClick(Sender: TObject);
procedure FormShow(Sender: TObject);
procedure ClientSocketConnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocketConnecting(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocketDisconnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure ClientSocketError(Sender: TObject; Socket: TCustomWinSocket;
ErrorEvent: TErrorEvent; var ErrorCode: Integer);
private
{ Private declarations }
public
{ Public declarations }
end;
var
frmClientMain: TfrmClientMain;
implementation
{$R *.DFM}
//打開套接字連接
procedure TfrmClientMain.tbConnectedClick(Sender: TObject);
begin
ClientSocket.Open ;
end;
//關閉套接字連接
procedure TfrmClientMain.tbDisconnectedClick(Sender: TObject);
begin
ClientSocket.Close;
end;
//接受服務器端的回復
procedure TfrmClientMain.ClientSocketRead(Sender: TObject;
Socket: TCustomWinSocket);
begin
Memo1.Lines.Add(Socket.ReceiveText);
end;
//發送信息到服務器端
procedure TfrmClientMain.tbSendClick(Sender: TObject);
begin
ClientSocket.Socket.SendText(Edit1.Text);
end;
procedure TfrmClientMain.tbCloseClick(Sender: TObject);
begin
Close;
end;
//設置要連接的服務器端地址
procedure TfrmClientMain.FormShow(Sender: TObject);
begin
ClientSocket.Host := SocketHost;
end;
//已經連接到服務器端
procedure TfrmClientMain.ClientSocketConnect(Sender: TObject;
Socket: TCustomWinSocket);
begin
tbSend.Enabled := True;
tbDisconnected.Enabled :=True;
btnSend.Enabled := True;
StatusBar.Panels[0].Text := '已經連接到 '+ Socket.RemoteHost ;
end;
//正在連接到服務器端
procedure TfrmClientMain.ClientSocketConnecting(Sender: TObject;
Socket: TCustomWinSocket);
begin
StatusBar.Panels[0].Text := '正在連接到服務器... ' ;
end;
//當斷開與服務器端的連接時發生
procedure TfrmClientMain.ClientSocketDisconnect(Sender: TObject;
Socket: TCustomWinSocket);
begin
tbSend.Enabled := False;
btnSend.Enabled := False;
tbDisconnected.Enabled := False;
StatusBar.Panels[0].Text := '已經斷開與 '+ Socket.RemoteHost +' 的連接';
end;
procedure TfrmClientMain.FormClose(Sender: TObject;
var Action: TCloseAction);
begin
ClientSocket.Close ;
end;
//當與服務器端的連接發生錯誤時
procedure TfrmClientMain.ClientSocketError(Sender: TObject;
Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
var ErrorCode: Integer);
begin
StatusBar.Panels[0].Text := '與服務器端的連接發生錯誤';
ErrorCode := 0;
end;
end.
小結
上述方法是比較簡單的實現方法，同時也是相對較容易理解的方法。通過這個方法，筆者成功實現了局域網內多個客戶端與服務器端進行Socket通信的功能，同時可以保證一個客戶端的連接、通信或是斷開都不影響其它客戶端的正常通信。
附錄：
服務器端窗體和客戶端窗體及組件的屬性設置參加相應的DFM文件。
uServerMain.pas對應的DFM文件(uServerMain.dfm)
object frmServerMain: TfrmServerMain
Left = 297
Top = 258
BorderIcons = [biSystemMenu, biMinimize]
BorderStyle = bsSingle
Caption = 'ServerSocket'
ClientHeight = 279
ClientWidth = 476
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OldCreateOrder = False
OnClose = FormClose
OnCreate = FormCreate
PixelsPerInch = 96
TextHeight = 13
object ControlBar1: TControlBar
Left = 0
Top = 0
Width = 476
Height = 30
Align = alTop
AutoSize = True
TabOrder = 0
object ToolBar1: TToolBar
Left = 11
Top = 2
Width = 459
Height = 22
ButtonHeight = 21
ButtonWidth = 55
Caption = 'ToolBar1'
EdgeInner = esNone
EdgeOuter = esNone
Flat = True
ShowCaptions = True
TabOrder = 0
object tbConnect: TToolButton
Left = 0
Top = 0
Caption = ' 連接 '
ImageIndex = 0
OnClick = tbConnectClick
end
object tbDisconnected: TToolButton
Left = 55
Top = 0
Caption = '斷開'
ImageIndex = 4
OnClick = tbDisconnectedClick
end
object tbClose: TToolButton
Left = 110
Top = 0
Caption = '關閉'
ImageIndex = 3
OnClick = tbCloseClick
end
end
end
object Edit1: TEdit
Left = 0
Top = 232
Width = 473
Height = 21
TabOrder = 1
Text = '你好！'
end
object Memo1: TMemo
Left = 0
Top = 30
Width = 476
Height = 195
Align = alTop
TabOrder = 2
end
object StatusBar: TStatusBar
Left = 0
Top = 257
Width = 476
Height = 22
Panels = <
item
Width = 50
end>
SimplePanel = False
end
object ServerSocket: TServerSocket
Active = False
Port = 1025
ServerType = stNonBlocking
OnListen = ServerSocketListen
OnGetSocket = ServerSocketGetSocket
OnClientConnect = ServerSocketClientConnect
OnClientDisconnect = ServerSocketClientDisconnect
OnClientRead = ServerSocketClientRead
OnClientError = ServerSocketClientError
Left = 368
end
end
uClientMain.pas對應的DFM文件(uClientMain.dfm)
object frmClientMain: TfrmClientMain
Left = 361
Top = 290
BorderIcons = [biSystemMenu, biMinimize]
BorderStyle = bsSingle
Caption = 'ClientSocket'
ClientHeight = 230
ClientWidth = 402
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OldCreateOrder = False
Position = poScreenCenter
OnClose = FormClose
OnShow = FormShow
PixelsPerInch = 96
TextHeight = 13
object ControlBar1: TControlBar
Left = 0
Top = 0
Width = 402
Height = 30
Align = alTop
AutoSize = True
TabOrder = 0
object ToolBar1: TToolBar
Left = 11
Top = 2
Width = 385
Height = 22
ButtonHeight = 21
ButtonWidth = 55
Caption = 'ToolBar1'
EdgeInner = esNone
EdgeOuter = esNone
Flat = True
ShowCaptions = True
TabOrder = 0
object tbConnected: TToolButton
Left = 0
Top = 0
Caption = ' 連接 '
ImageIndex = 0
OnClick = tbConnectedClick
end
object tbSend: TToolButton
Left = 55
Top = 0
Caption = '發送'
Enabled = False
ImageIndex = 1
OnClick = tbSendClick
end
object tbDisconnected: TToolButton
Left = 110
Top = 0
Caption = '斷開'
Enabled = False
ImageIndex = 3
OnClick = tbDisconnectedClick
end
object tbClose: TToolButton
Left = 165
Top = 0
Caption = '退出'
ImageIndex = 2
OnClick = tbCloseClick
end
end
end
object Edit1: TEdit
Left = 0
Top = 184
Width = 321
Height = 21
TabOrder = 1
Text = '問候'
end
object Memo1: TMemo
Left = 0
Top = 30
Width = 402
Height = 147
Align = alTop
TabOrder = 2
end
object StatusBar: TStatusBar
Left = 0
Top = 208
Width = 402
Height = 22
Panels = <
item
Width = 50
end>
SimplePanel = False
end
object btnSend: TBitBtn
Left = 336
Top = 183
Width = 60
Height = 22
Caption = '發送'
Enabled = False
TabOrder = 4
OnClick = tbSendClick
end
object ClientSocket: TClientSocket
Active = False
ClientType = ctNonBlocking
Port = 1025
OnConnecting = ClientSocketConnecting
OnConnect = ClientSocketConnect
OnDisconnect = ClientSocketDisconnect
OnRead = ClientSocketRead
OnError = ClientSocketError
Left = 320
end
end