1：通过java运行cmd命令，来通过arp命令获取同一网络下设备信息，对于支持linux 和windows的设备有效，像一些非智能设备，就无力回天了
2：使用android手机通过向子网内所有设备先发送一遍udp包，实现与在线的设备都进行通信一遍，这样对应的路由信息就自动存储在本地手机中，然后在通过读取android 本机的arp缓存表，来获取设备信息
好，下面详细进行第二种方式的描述：
Step1：首先，获取本机所处的子网段，方法详细代码如下：
/**
* 获取ip地址
*
* @return
*/
private static String getHostIP() {
String hostIp = null;
try {
//这里以eth0为例
hostIp = getIpAddress("eth0");
} catch (SocketException e) {
e.printStackTrace();
}
return hostIp;
}
/**
* Get Ip address 自动获取IP地址
* 可以传入eth1，eth0,wlan0,等
*
* @throws SocketException
*/
public static String getIpAddress(String ipType) throws SocketException {
String hostIp = null;
try {
Enumeration nis = NetworkInterface.getNetworkInterfaces();
InetAddress ia = null;
while (nis.hasMoreElements()) {
NetworkInterface ni = (NetworkInterface) nis.nextElement();
if (ni.getName().equals(ipType)) {
Enumeration<InetAddress> ias = ni.getInetAddresses();
while (ias.hasMoreElements()) {
ia = ias.nextElement();
if (ia instanceof Inet6Address) {
continue;// skip ipv6
}
String ip = ia.getHostAddress();
// 过滤掉127段的ip地址
if (!"127.0.0.1".equals(ip)) {
hostIp = ia.getHostAddress();
break;
}
}
}
}
} catch (SocketException e) {
e.printStackTrace();
}
Log.d(ipType, "get the IpAddress--> " + hostIp + "");
return hostIp;
}
Step2:new出一个线程，向网段内所有在线设备发送消息。
/**
* 创建一个线程向本地所有ip发送一个数据
*/
public static void sendDataToLocal() {
//局域网内存在的ip集合
final List<String> ipList = new ArrayList<>();
final Map<String, String> map = new HashMap<>();
//获取本机所在的局域网地址
String hostIP = getHostIP();
int lastIndexOf = hostIP.lastIndexOf(".");
final String substring = hostIP.substring(0, lastIndexOf + 1);
new Thread(new Runnable() {
@Override
public void run() {
DatagramPacket dp = new DatagramPacket(new byte[0], 0, 0);
DatagramSocket socket;
try {
socket = new DatagramSocket();
int position = 2;
while (position < 255) {
Log.e("Scanner ", "run: udp-" + substring + position);
dp.setAddress(InetAddress.getByName(substring + String.valueOf(position)));
socket.send(dp);
position++;
if (position == 125) {
//分两段掉包，一次性发的话，达到236左右，会耗时3秒左右再往下发
socket.close();
socket = new DatagramSocket();
}
}
socket.close();
} catch (SocketException e) {
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
执行完后会自动写入到/proc/net/arp
目录下，如下：
Step3:延时3秒后，读取本机proc/net/arp目录下的内容，得到结果：
/**
* 读取/proc/net/arp并且解析出来ip，mac,flag
* flag 为0x00说明目前不在局域网内，曾经在过.0x02代表在局域网内
*/
public static void readArp() {
try {
BufferedReader br = new BufferedReader(new FileReader("/proc/net/arp"));
String line = "";
String ip = "";
//flag 为0x00说明目前不在局域网内，曾经在过.0x02代表在局域网内
String flag = "";
String mac = "";
if (br.readLine() == null) {
Log.e("scanner", "readArp: null");
}
while ((line = br.readLine()) != null) {
line = line.trim();
if (line.length() < 63)
continue;
if (line.toUpperCase(Locale.US).contains("IP"))
continue;
ip = line.substring(0, 17).trim();
flag = line.substring(29, 32).trim();
mac = line.substring(41, 63).trim();
if (mac.contains("00:00:00:00:00:00"))
continue;
Log.e("scanner", "readArp: mac= " + mac + " ; ip= " + ip + " ;flag= " + flag);
}
br.close();
} catch (Exception ignored) {
}
}
打印日志如下
最后附上完整代码
public class DiscoverNetIpUtil{
/**
* 获取ip地址
*
* @return
*/
private static String getHostIP() {
String hostIp = null;
try {
//这里以eth0为例
hostIp = getIpAddress("eth0");
} catch (SocketException e) {
e.printStackTrace();
}
return hostIp;
}
/**
* Get Ip address 自动获取IP地址
* 可以传入eth1，eth0,wlan0,等
*
* @throws SocketException
*/
public static String getIpAddress(String ipType) throws SocketException {
String hostIp = null;
try {
Enumeration nis = NetworkInterface.getNetworkInterfaces();
InetAddress ia = null;
while (nis.hasMoreElements()) {
NetworkInterface ni = (NetworkInterface) nis.nextElement();
if (ni.getName().equals(ipType)) {
Enumeration<InetAddress> ias = ni.getInetAddresses();
while (ias.hasMoreElements()) {
ia = ias.nextElement();
if (ia instanceof Inet6Address) {
continue;// skip ipv6
}
String ip = ia.getHostAddress();
// 过滤掉127段的ip地址
if (!"127.0.0.1".equals(ip)) {
hostIp = ia.getHostAddress();
break;
}
}
}
}
} catch (SocketException e) {
e.printStackTrace();
}
Log.d(ipType, "get the IpAddress--> " + hostIp + "");
return hostIp;
}
/**
* 创建一个线程向本地所有ip发送一个数据
*/
public static void sendDataToLocal() {
//局域网内存在的ip集合
final List<String> ipList = new ArrayList<>();
final Map<String, String> map = new HashMap<>();
//获取本机所在的局域网地址
String hostIP = getHostIP();
int lastIndexOf = hostIP.lastIndexOf(".");
final String substring = hostIP.substring(0, lastIndexOf + 1);
new Thread(new Runnable() {
@Override
public void run() {
DatagramPacket dp = new DatagramPacket(new byte[0], 0, 0);
DatagramSocket socket;
try {
socket = new DatagramSocket();
int position = 2;
while (position < 255) {
Log.e("Scanner ", "run: udp-" + substring + position);
dp.setAddress(InetAddress.getByName(substring + String.valueOf(position)));
socket.send(dp);
position++;
if (position == 125) {
//分两段掉包，一次性发的话，达到236左右，会耗时3秒左右再往下发
socket.close();
socket = new DatagramSocket();
}
}
socket.close();
} catch (SocketException e) {
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
/**
* 读取/proc/net/arp并且解析出来ip，mac,flag
* flag 为0x00说明目前不在局域网内，曾经在过.0x02代表在局域网内
*/
public static void readArp() {
try {
BufferedReader br = new BufferedReader(new FileReader("/proc/net/arp"));
String line = "";
String ip = "";
//flag 为0x00说明目前不在局域网内，曾经在过.0x02代表在局域网内
String flag = "";
String mac = "";
if (br.readLine() == null) {
Log.e("scanner", "readArp: null");
}
while ((line = br.readLine()) != null) {
line = line.trim();
if (line.length() < 63)
continue;
if (line.toUpperCase(Locale.US).contains("IP"))
continue;
ip = line.substring(0, 17).trim();
flag = line.substring(29, 32).trim();
mac = line.substring(41, 63).trim();
if (mac.contains("00:00:00:00:00:00"))
continue;
Log.e("scanner", "readArp: mac= " + mac + " ; ip= " + ip + " ;flag= " + flag);
}
br.close();
} catch (Exception ignored) {
}
}
}