普通的域名解析方法：

import java.net.*;

public class Kkkk {

public static void main(String args[]) throws Exception {

InetAddress address = InetAddress.getByName("wxh-PC");// wxh-PC是我的计算机名

System.out.println(address);

System.out.println("-----");

InetAddress address1 = InetAddress.getLocalHost();

System.out.println(address1);

InetAddress[] addresses = InetAddress

.getAllByName("www.baidu.com");

System.out.println(addresses.length);

for (InetAddress addr : addresses) {

System.out.println(addr);

}

}

}

实现具有动态主机IP的域名解析

目的利用一台INTERNET DNS HOST 将域名定向到家中(个人)的主机上.

目前CABLEMODEM已经很快了,而且有动态IP,所以就有了将域名解析到个人机器的上可能.

只要通过很简单的设置就可以搞定.

例如你有一个域名叫 yourdomain.com ,你可以将此域名解析任意的主机.

1.服务器 (IP: A.A.A.A)　启动DNS动态解析的一个小进程.

ctolib.com的域名文件为 /var/named/ctolib.com

再建个/var/named/ctolib.com.static (模板文件可以用来生成ctolib.com的)

(JDK1.3 , linux )

#　原代码如下: ThreadDNSReloadServer.java

import java.io.*;

import java.net.*;

public class ThreadDNSReloadServer

{　 public static void main(String[] args)

{ int i=1;

try

{　ServerSocket s=new ServerSocket(8189);

for (;;)

{　Socket incoming =s.accept();

System.out.println("accept new client: " + i);

new ThreadDNSReloadHandle(incoming,i).start();

i++ ;

}

}

catch (Exception e)

{ System.out.println(e);

}

}

}

class ThreadDNSReloadHandle extends Thread

{ public ThreadDNSReloadHandle(Socket i,int c)

{ incoming= i; counter=c; }

public void run()

{ try

{ BufferedReader in=new BufferedReader(new InputStreamReader(incoming.getInputStream()));

String User="Unkown";

String DNSFILEPATH="/var/named/";

String DNSFILE="ctolib.com";

String HOSTIP="127.0.0.1";

boolean USER_VALIDATED=true ;

boolean done=false;

while ( !done )

{　 String str=in.readLine();

//validate user;

if ( str ==null ) done=true;

else

{

str=str.trim();

if ( str.substring(0,2).equals("LA") )

{ if (str.length() >2)　User=str.substring(2);

}

if ( str.substring(0,2).equals("LB") )

{ if (str.length() >2) DNSFILE=str.substring(2);

}

if ( str.substring(0,2).equals("LC") )

{ if (str.length() >2) HOSTIP=str.substring(2);

}

if ( str.trim().equals("BYE")) done = true;

}

}

incoming.close();

//加入用户验证.

//将服务器中的ctolib.com.static文件写入ctolib.com中

String DNSTMP =DNSFILEPATH + DNSFILE +".static";

BufferedReader sin=new BufferedReader(new FileReader(DNSTMP));

PrintWriter sout=new PrintWriter(new FileWriter(DNSFILEPATH + DNSFILE) , true);

String s;

while ((s=sin.readLine()) != null)

{

if (s.startsWith("host"))

{ s="host IN A " + HOSTIP;

sout.println(s);

s="@ IN A " + HOSTIP;

}

sout.println(s);

}

//System.out.println("User:" + User );

//System.out.println("DNSFILE:" + DNSFILE );

//System.out.println("HOSTIP:" + HOSTIP );

//ndc reload

String command="ndc reload " + DNSFILE ;

java.lang.Runtime.getRuntime().exec(command);

}

catch ( Exception e)

{ System.out.println(e);

}

}

private Socket incoming;

private int counter;

}

2.客户机(windows / linux)

# 客户端每次启动时加入到开机启动(或进程中): SockTest.java

import java.io.*;

import java.net.*;

public class SocketTest

{　public static void main(String[] args)

{ try

{ Socket s=new Socket("A.A.A.A",8189);

BufferedReader in=new BufferedReader(new InputStreamReader(s.getInputStream()));

PrintWriter out=new PrintWriter(s.getOutputStream(),true);

InetAddress localHostAddress =InetAddress.getLocalHost() ;　//get LocalHost Ip

out.println("LAguest");

out.println("LByourdomain.com");

out.println("LC" + localHostAddress.getHostAddress()　);

out.close();

s.close();

}

catch (IOException e)

{ System.out.println(e);

}

}

}

dns 样本文件: ( ctolib.com.static)

@ ns.dnsserver.com　xxxxx

xxxx

host　　　 IN A 127.0.0.1　　　　　 // 此处就是要更改的地方

www　　　　IN CNAME host

...