IP与主机名的转换

Question

在局域网内实现IP与主机名的转换，
给定主机名测试出其IP

Answer 1

ping -a <主机名>然后取出ip

Answer 2

给你一段程序：unit UnitDNS;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls,Winsock;type
  TFormMain = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    EditPresentation: TEdit;
    EditResult: TEdit;
    edtHost: TEdit;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  FormMain: TFormMain;implementation{$R *.DFM}procedure TFormMain.FormCreate(Sender: TObject);
Var
   WSAData:TWSAData;
begin
     //initiates use of WS2_32.DLL
     if (WSAStartup(MAKEWORD(2,0),WSAData)<>0) then
        raise Exception.Create('Winsock Version Error');
end;procedure TFormMain.FormDestroy(Sender: TObject);
begin
     WSACleanUP;
end;
procedure TFormMain.Button1Click(Sender: TObject);
var
   Host: pHostent;
   ConsultResult:String;
   Err:Integer;
begin
     Try
        Host := GetHostByName(PChar(EditPresentation.Text));
     Except
        Err:=WSAGetLastError();
        EditResult.Text:='Error Code:'+InttoStr(Err);
        Exit;
     end;
     if Host=NIL then
     begin
        EditResult.Text:='Host does not exist';
        exit;
     end;
     ConsultResult:=Copy(Host.h_addr^,0,4);
     EditResult.Text:=Format('%d.%d.%d.%d',
                              [ord(ConsultResult[1]),
                               ord(ConsultResult[2]),
                               ord(ConsultResult[3]),
                               ord(ConsultResult[4])]);
     edtHost.Text:=Host.h_name;
end;end.

Answer 3

用 WSAAsyncGetHoostByName；
USES 
  WinSock;
.....
private
  hAsyncTaskHandle: THandle;
  procedure WMRESOLVED(var msg:TMSG);
.....
var 
  buff: HOSTENT; 
.....
begin
  hAsyncTaskHandle := WSAAsyncGetHostByName(Handle, WM_RESOLVED,
                                            PChar(<域名>),PChar(@buff),
                                            MAXGETHOSTSTRUCT);
end;
procedure TForm1.WMRESOLVED(var msg: TMSG)
begin
  if buf.h_addr = nil then
    <出错>
  else
  begin
    <主机名> := buff.h_name;
    <IP> := Format('%d.%d.%d.%d',
                   [ord(ConsultResult[1]), ord(ConsultResult[2]),
                   ord(ConsultResult[3]),ord(ConsultResult[4])]);
  end;
end;
.....
如果等待时间过长可用 WSACancelAsyncRequest(hAsyncTaskHandle); 中断解析。

Answer 4

用 WSAAsyncGetHoostByName；
USES 
  WinSock;
const 
  WM_RESOLVED = WM_USER + 1001;
.....
private
  hAsyncTaskHandle: THandle;
  procedure WMRESOLVED(var msg:TMSG); message WM_RESOLVED;
.....
var 
  buff: HOSTENT; 
.....
begin
  hAsyncTaskHandle := WSAAsyncGetHostByName(Handle, WM_RESOLVED,
                                            PChar(<域名>),PChar(@buff),
                                            MAXGETHOSTSTRUCT);
end;
procedure TForm1.WMRESOLVED(var msg: TMSG)
begin
  if buf.h_addr = nil then
    <出错>
  else
  begin
    <主机名> := buff.h_name;
    <IP> := Format('%d.%d.%d.%d',
                   [ord(ConsultResult[1]), ord(ConsultResult[2]),
                   ord(ConsultResult[3]),ord(ConsultResult[4])]);
  end;
end;
.....
如果等待时间过长可用 WSACancelAsyncRequest(hAsyncTaskHandle); 中断解析。
刚才写的有点错，不好意思。