作者：steeven
email: [email protected]

扫描500个IP10秒钟左右, 一个IP等待0.3秒
说来惭愧, 我觉得是用java写的过程编程, 少贴一点仅供参考:
package steeven;

import java.sql.*;
import java.io.*;
import java.util.*;
import java.text.*;
import javax.servlet.http.*;

public class Ip extends Common implements Runnable{

public String ip; // IP, 用户名, 主机名

ResultSet list; // 分页显示的记录集
public Ip cur; // 分页显示的当前记录

static public Hashtable ping = new Hashtable(); //ping 后的结果集
static int threadCount = 0; //当前线程的数量, 防止过多线程摧毁电脑


public Ip() {}
public Ip(String ip){
this.ip=ip;
Thread r = new Thread(this);
r.start();
}

public static void Ping(String ip) throws Exception{
//最多30个线程
while(threadCount>30)
Thread.sleep(50);
threadCount +=1;
Ip p = new Ip(ip);
}
public void PingAll() throws Exception{
threadCount =0;
ping = new Hashtable();
while(next()) //next()对所有局域网Ip放到cur
Ping(cur.ip);
//等着所有Ping结束
while(threadCount>0)
Thread.sleep(50);
}
public void run(){
try{
Process p= Runtime.getRuntime().exec ("ping "+ip+ " -w 300 -n 1");
InputStreamReader ir = new InputStreamReader(p.getInputStream());
LineNumberReader input = new LineNumberReader (ir);
//读取结果行
for (int i=1 ; i<7; i++)
input.readLine();
String line= input.readLine();

if (line.length()<17 || line.substring(8,17).equals("timed out"))
ping.put(ip,new Boolean(false));
else
ping.put(ip,new Boolean(true));
//线程结束
threadCount -= 1;
}catch (IOException e){}
}
public static void main(String[] args) throws Exception{
Ip ip= new Ip();
ip.PingAll();
java.util.Enumeration key = ping.keys();
String k;
while((k = (String)key.nextElement()) != null)
System.out.println(k+": "+ping.get(k));
}
}

1. 利用Ping比较愚蠢, 但是相对简单些
2. 如果Ping 成功后, 用nbtstat还可以得到主机名, 当前用户名, MAC地址...一切尽在掌握中 :)