在Delphi中关于UDP协议的实现

原文地址：在Delphi中关于UDP协议的实现作者：菜心

首先我把UDP无连接协议的套接字调用时序图表示出来

在我把在Delphi中使用UDP协议实现数据通讯收发的实现方法总结如下:

  例子描述:下面例子是我的一个实际设备通讯的例子,使用UDP协议在4660端口上发送'F1,00'(16进制,2个字节),在同一个端口上接收到'F1,00,00,00,00,00'((16进制,2个字节))

1.使用底层函数来实现

procedure TForm1.FormCreate(Sender: TObject);
var
    WSAData:TWSAData;
begin
    edtHost.Text:=192.168.1.222';
    edtPort.Text:='4660';
//1.初始化Winsock
    if (WSAStartup(MAKEWORD(2,0),WSAData)<>0) then
    begin
        //初始化失败
        memInfo.Lines.Add('Winsock Init Failed');
        exit;
    end
    else
        memInfo.Lines.Add('Socket Start');
end;
procedure TForm1.btnFingerClick(Sender: TObject);
var
    Info:string;
    BufSend,BufRecv:array[0..1024] of byte;
    skt:TSOCKET;
    addr:TSockAddr;
    Re:Integer;
    S:String;
    i:Integer;
begin

//=====================数据发送=========================================
   //2.建立socket
    skt:=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
    if(skt=INVALID_SOCKET)then
    begin
        memInfo.Lines.Add('Error:Create socket failed!');
        exit;
    end;
   //3.连接主机
    ZeroMemory(@addr,sizeof(addr));
    addr.sin_family :=AF_INET;
    addr.sin_addr.s_addr :=inet_addr('192.168.1.222');
    addr.sin_port:=htons(4660);
    Re := connect(skt,addr,sizeof(addr));
    if(Re<>0)then
    begin
         memInfo.Lines.Add('Connect to server failed');
         exit;
    end;
  //4.发送信息
    BufSend[0]:=$F1;
    BufSend[1]:=0;
    Re:=send(skt,BufSend,2,0);
    if(Re=SOCKET_ERROR)then
    begin
         memInfo.Lines.Add('Send Data Failed');
         exit;
    end;
  //6.关闭socket
    closesocket(skt);

//=============接收数据的==================================

   //2.建立socket
    skt:=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
    if(skt=INVALID_SOCKET)then
    begin
        memInfo.Lines.Add('Error:Create socket failed!');
        exit;
    end;
   //3.绑定主机
    ZeroMemory(@addr,sizeof(addr));
    addr.sin_family :=AF_INET;
    addr.sin_addr.s_addr :=inet_addr('192.168.1.106');
    addr.sin_port:=htons(4660);
    Re := Bind(skt,addr,sizeof(addr));
    if(Re<>0)then
    begin
         memInfo.Lines.Add('Connect to server failed');
         exit;
    end;
   //4.接收信息
    Re:=Recv(skt,BufRecv,6,0);
    if(Re=SOCKET_ERROR)then
    begin
         memInfo.Lines.Add('Send Data Failed');
         exit;
    end
    else
    begin
      S:='';
      for i:=0 to Re-1 do
      begin
        S:=S+IntToHex(Integer(BufRecv[i]),2);
      end;
      memInfo.Lines.Add(S);
    end;
  //6.关闭socket
    closesocket(skt);
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
//6.释放Winsock
WSACleanUP();
end;

2.使用TUDPSocket组件实现

TUDPSocket组件是继承于TCustomIPClient的。它被设计为只能当作一个客户端来用

所以它是不能直接用来接收数据的,要是实现接收必须另外定义一个接收的TIPSocket,重新绑定接口.

 type
  TForm2 = class(TForm)
    UdpSocket1: TUdpSocket;
    Button1: TButton;
    UdpSocket2: TUdpSocket;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    aUDPServer:TIPSocket;
  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}

procedure TForm2.FormCreate(Sender: TObject);
var
   addr:sockAddr_In;
begin
  UdpSocket1.RemoteHost:='192.168.1.222';
  UdpSocket1.RemotePort:='4660';
  UdpSocket1.Open ;

  aUDPServer:=TIPSocket.Create(nil);
  aUDPServer.RemoteHost:='192.168.1.222';
  aUDPServer.RemotePort:='4660';
  aUDPServer.LocalHost:=aUDPServer.LocalHostName;
  aUDPServer.LocalPort:='4660';
  aUDPServer.Protocol:=IPPROTO_UDP;
  aUDPServer.SockType:=stDgram;
  aUDPServer.Active:=true;
  addr:=aUDPServer.GetSocketAddr(aUDPServer.LocalHost,aUDPServer.LocalPort);
  bind(aUDPServer.Handle,addr,sizeof(addr));

end;

procedure TForm2.Button1Click(Sender: TObject);
var
  ReceivedString:string;
  Buff:array[0..1] of byte;
  RevBuf:array[0..1024] of byte;
  RevSize:Integer;
  i:Integer;
  S:string;
  ToAddr:sockAddr_In;
  Len:integer;
  a:in_Addr;
begin
    Buff[0]:=$F1;
    Buff[1]:=0;
    UdpSocket1.SendBuf(Buff,2);
    ToAddr:=UdpSocket2.GetSocketAddr(UdpSocket2.LocalHost,UdpSocket2.LocalPort);
     bind(UdpSocket2.Handle,ToAddr,sizeof(ToAddr));
    RevSize:=UdpSocket2.ReceiveBuf(RevBuf,6) ;
    S:='';
    for i:=0 to RevSize-1 do
    begin
      S:=S+IntToHex(Integer(RevBuf[i]),2);
    end;
      ShowMessage(S);
end;
3.使用TIdUDPClient组件实现

TIdUDPClient组件中重新绑定了一个Socket,用来专门接收数据,所以本身一个组件就可以实现接收

procedure TForm1.Button1Click(Sender: TObject);
var
  ReceivedString:string;
  Buff:array[0..1] of byte;
  RevBuf:array[0..1024] of byte;
  RevSize:Integer;
  i:Integer;
  S:string;
begin
    Buff[0]:=$F1;
    Buff[1]:=0;
    IdUDPClient1.SendBuffer(Buff,2);
    RevSize:=IdUDPClient1.Binding.Recv(RevBuf,6,0);
    S:='';
    for i:=0 to RevSize-1 do
    begin
      S:=S+IntToHex(Integer(RevBuf[i]),2);
    end;
      ShowMessage(S);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
    IdUDPClient1.Host:='192.168.1.222';
    IdUDPClient1.Binding.Port:=4660;
    IdUDPClient1.Binding.Bind;
    IdUDPClient1.Active:=True;

end;
3.使用TNMUDP组件实现

这里我发现在第一次运行时,要连续按两次按钮,才能收到数据

procedure TForm1.BitBtn2Click(Sender: TObject);
var
  Buf:array[0..1] of char;
  RevBuf :array[0..1024] of char;
  ss:string;
  i:integer;
  Len:Integer;
begin

 Buf[0]:=char($F1);
 Buf[1]:=char(0);
 NMUDP1.SendBuffer(Buf[0],2);
 NMUDP1.ReadBuffer(RevBuf[0],Len);
 if Len>0 then
 begin
     ss:='';
    for i:=1 to Len do
    begin
     ss:=ss + intToHex(integer(RevBuf[i]),2);
    end;
    ShowMessage(ss);
 end;

end;

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