Esta es mi utilidad auxiliar para leer direcciones IP y MAC. La implementación es puramente java, pero tengo un bloque de comentarios en el getMACAddress()que podría leer el valor del archivo especial de Linux (Android). Ejecuté este código solo en algunos dispositivos y en el emulador, pero avíseme aquí si encuentra resultados extraños.
// AndroidManifest.xml permissions
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
// test functions
Utils.getMACAddress("wlan0");
Utils.getMACAddress("eth0");
Utils.getIPAddress(true); // IPv4
Utils.getIPAddress(false); // IPv6
Utils.java
import java.io.*;
import java.net.*;
import java.util.*;
//import org.apache.http.conn.util.InetAddressUtils;
public class Utils {
/**
* Convert byte array to hex string
* @param bytes toConvert
* @return hexValue
*/
public static String bytesToHex(byte[] bytes) {
StringBuilder sbuf = new StringBuilder();
for(int idx=0; idx < bytes.length; idx++) {
int intVal = bytes[idx] & 0xff;
if (intVal < 0x10) sbuf.append("0");
sbuf.append(Integer.toHexString(intVal).toUpperCase());
}
return sbuf.toString();
}
/**
* Get utf8 byte array.
* @param str which to be converted
* @return array of NULL if error was found
*/
public static byte[] getUTF8Bytes(String str) {
try { return str.getBytes("UTF-8"); } catch (Exception ex) { return null; }
}
/**
* Load UTF8withBOM or any ansi text file.
* @param filename which to be converted to string
* @return String value of File
* @throws java.io.IOException if error occurs
*/
public static String loadFileAsString(String filename) throws java.io.IOException {
final int BUFLEN=1024;
BufferedInputStream is = new BufferedInputStream(new FileInputStream(filename), BUFLEN);
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream(BUFLEN);
byte[] bytes = new byte[BUFLEN];
boolean isUTF8=false;
int read,count=0;
while((read=is.read(bytes)) != -1) {
if (count==0 && bytes[0]==(byte)0xEF && bytes[1]==(byte)0xBB && bytes[2]==(byte)0xBF ) {
isUTF8=true;
baos.write(bytes, 3, read-3); // drop UTF8 bom marker
} else {
baos.write(bytes, 0, read);
}
count+=read;
}
return isUTF8 ? new String(baos.toByteArray(), "UTF-8") : new String(baos.toByteArray());
} finally {
try{ is.close(); } catch(Exception ignored){}
}
}
/**
* Returns MAC address of the given interface name.
* @param interfaceName eth0, wlan0 or NULL=use first interface
* @return mac address or empty string
*/
public static String getMACAddress(String interfaceName) {
try {
List<NetworkInterface> interfaces = Collections.list(NetworkInterface.getNetworkInterfaces());
for (NetworkInterface intf : interfaces) {
if (interfaceName != null) {
if (!intf.getName().equalsIgnoreCase(interfaceName)) continue;
}
byte[] mac = intf.getHardwareAddress();
if (mac==null) return "";
StringBuilder buf = new StringBuilder();
for (byte aMac : mac) buf.append(String.format("%02X:",aMac));
if (buf.length()>0) buf.deleteCharAt(buf.length()-1);
return buf.toString();
}
} catch (Exception ignored) { } // for now eat exceptions
return "";
/*try {
// this is so Linux hack
return loadFileAsString("/sys/class/net/" +interfaceName + "/address").toUpperCase().trim();
} catch (IOException ex) {
return null;
}*/
}
/**
* Get IP address from first non-localhost interface
* @param useIPv4 true=return ipv4, false=return ipv6
* @return address or empty string
*/
public static String getIPAddress(boolean useIPv4) {
try {
List<NetworkInterface> interfaces = Collections.list(NetworkInterface.getNetworkInterfaces());
for (NetworkInterface intf : interfaces) {
List<InetAddress> addrs = Collections.list(intf.getInetAddresses());
for (InetAddress addr : addrs) {
if (!addr.isLoopbackAddress()) {
String sAddr = addr.getHostAddress();
//boolean isIPv4 = InetAddressUtils.isIPv4Address(sAddr);
boolean isIPv4 = sAddr.indexOf(':')<0;
if (useIPv4) {
if (isIPv4)
return sAddr;
} else {
if (!isIPv4) {
int delim = sAddr.indexOf('%'); // drop ip6 zone suffix
return delim<0 ? sAddr.toUpperCase() : sAddr.substring(0, delim).toUpperCase();
}
}
}
}
}
} catch (Exception ignored) { } // for now eat exceptions
return "";
}
}
Descargo de responsabilidad: las ideas y el código de ejemplo para esta clase de Utils provienen de varias publicaciones SO y Google. He limpiado y fusionado todos los ejemplos.