1. 经常用法，调用Android的API：WifiManager

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>

WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo info = wifi.getConnectionInfo();
return info.getMacAddress();
 

此方法须要保证WIFI在本次开机以来以前是打开过的，否则会返回null。所以须要后台尝试先打开WIFI再获取。

演示样例代码：

//尝试打开wifi
private static boolean tryOpenMAC(WifiManager manager)
{
    boolean softOpenWifi = false;
    int state = manager.getWifiState();
    if (state != WifiManager.WIFI_STATE_ENABLED && state != WifiManager.WIFI_STATE_ENABLING)
    {
        manager.setWifiEnabled(true);
        softOpenWifi = true;
    }
    return softOpenWifi;
}

//尝试关闭MAC
private static void tryCloseMAC(WifiManager manager)
{
    manager.setWifiEnabled(false);
}

//尝试获取MAC地址
private static String tryGetMAC(WifiManager manager)
{
    WifiInfo wifiInfo = manager.getConnectionInfo();
    if (wifiInfo == null || StringUtil.isNull(wifiInfo.getMacAddress()))
    {
        return null;
    }
    String mac = wifiInfo.getMacAddress().replaceAll(":", "").trim().toUpperCase();
    mac = formatIdentify(mac);
    return mac;
}

//尝试读取MAC地址
private static String getMacFromDevice(int internal)
{
    String mac=null;
    WifiManager wifiManager = (WifiManager)getSystemService(Context.WIFI_SERVICE); 
    mac = tryGetMAC(wifiManager);
    if(!StringUtil.isNull(mac))
    {
        return mac;
    }
 
    //获取失败，尝试打开wifi获取
    boolean isOkWifi = tryOpenMAC(wifiManager);
    for(int index=0;index<internal;index++)
    {
        //假设第一次没有成功，第二次做100毫秒的延迟。
        if(index!=0)
        {
            try
            {
                Thread.sleep(100);
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
        }
        mac = tryGetMAC(wifiManager);
        if(!StringUtil.isNull(mac))
        {
            break;
        }
    }

    //尝试关闭wifi
    if(isOkWifi)
    {
        tryCloseMAC(wifiManager);
    }
    return mac;
}

==================================================================

2. 查询文件路径 /sys/class/net/wlan0/address

adb shell cat /sys/class/net/wlan0/address

98:6c:f5:10:96:c4

可是假设WIFI在本次开机期间从来没有打开过，返回的MAC地址是不同的（非实际的），例如以下：

cat /sys/class/net/wlan0/address
00:90:4c:11:22:33

演示样例代码：

           String getMac() {
                String macSerial = null;
                String str = "";
                try {
                        Process pp = Runtime.getRuntime().exec("cat /sys/class/net/wlan0/address");
                        InputStreamReader ir = new InputStreamReader(pp.getInputStream());
                        LineNumberReader input = new LineNumberReader(ir);

                        for (; null != str;) {
                                str = input.readLine();
                                if (str != null) {
                                        macSerial = str.trim();
                                        break;
                                }
                        }
                } catch (IOException e) {
                        e.printStackTrace();
                }
                return macSerial;
        }
==================================================================

3. 查询记录了MAC地址的文件“/proc/net/arp”，可是从測试结果看，返回的数据并非想要的Wifi Mac地址：

比方，手机实际的WIFI Mac地址是98:6c:f5:10:96:c4，但使用adb shell cat proc/net/arp返回的是：

cat proc/net/arp
IP address       HW type     Flags       HW address            Mask     Device
192.168.0.3      0x1         0x2         00:23:89:b9:1a:fd     *        wlan0
192.168.0.1      0x1         0x2         08:00:27:7c:65:5a     *        wlan0