Java语言列举所有局域网上打开的计算机的计算机名和ip，并且放在数组中，怎么写

Java语言列举所有局域网上打开的计算机的计算机名和ip，并且放在数组中，怎么写

代码如下，需要根据自己情况做调整：

执行外部命令

String command = "net view"
Runtime r = Runtime.getRuntime();
Process p = r.exec(command);
BufferedReader br = new BufferedReader(new InputStreamReader(p
.getInputStream()));

提取局域网IP
public static List getIPs()
{
List list = new ArrayList();
boolean flag = false;
int count=0;
Runtime r = Runtime.getRuntime();
Process p;
try {
p = r.exec("arp -a");
BufferedReader br = new BufferedReader(new InputStreamReader(p
.getInputStream()));
String inline;
while ((inline = br.readLine()) != null) {
if(inline.indexOf("接口") > -1){
flag = !flag;
if(!flag){
//碰到下一个"接口"退出循环
break;
}
}
if(flag){
count++;
if(count > 2){
//有效IP
String[] str=inline.split(" {4}");
list.add(str[0]);
}
}
System.out.println(inline);
}
br.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(list);
return list;
}

根据IP提取主机名
public static Map getHostnames(List ips){

    Map<String,String> map = new HashMap<String,String>();
    System.out.println("正在提取hostname...");
    for(String ip : ips){
        String command = "ping -a " + ip;
        Runtime r = Runtime.getRuntime();
        Process p;
        try {
            p = r.exec(command);
            BufferedReader br = new BufferedReader(new InputStreamReader(p
                    .getInputStream()));
            String inline;
            while ((inline = br.readLine()) != null) {
                if(inline.indexOf("[") > -1){
                    int start = inline.indexOf("Ping ");
                    int end = inline.indexOf("[");
                    String hostname = inline.substring(start+"Ping ".length(),end-1);
                    System.out.println(hostname);
                    map.put(ip,hostname);
                }
            }
            br.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    System.out.println("提取结束！");
    return map;
}