使用java獲取本機mac

不開心，辛苦寫的第一篇文章不小心刪除了還恢復不了

想用java 獲得本機地址，搜了下，覺得這個看起來不錯，簡潔

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;

public class app{

   public static void main(String[] args){

    InetAddress ip;
    try {

        ip = InetAddress.getLocalHost();
        System.out.println("Current IP address : " + ip.getHostAddress());

        NetworkInterface network = NetworkInterface.getByInetAddress(ip);

        byte[] mac = network.getHardwareAddress();

        System.out.print("Current MAC address : ");

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < mac.length; i++) {
            sb.append(String.format("%02X%s", mac[i], (i < mac.length - 1) ? "-" : ""));        
        }
        System.out.println(sb.toString());

    } catch (UnknownHostException e) {

        e.printStackTrace();

    } catch (SocketException e){

        e.printStackTrace();

    }

   }

}

　　好多都是這個版本，問題在於，一運行，報錯了！！很無語，排查了很久也找不到原因，看getHardwareAddress API也沒發現錯誤，很無奈。

mei@mei-X-Series:~/mei/test$ java Ipconfig 
mei-X-Series/127.0.1.1
Exception in thread "main" java.lang.NullPointerException
    at Ipconfig.getLocalMac(Ipconfig.java:24)
    at Ipconfig.main(Ipconfig.java:19)

　　終於在http://rupertanderson.com/blog/soapui-google-analytics-null-pointer-exception-on-ubuntu/ 中找到難友，並獲知了原因，that NetworkInterface.getByInetAddress cannot match the Machine Name to any of the Network Interface values.就是不匹配了。 

 　　超出了自己的能力范圍，看來智能用復雜的代碼了，以下代碼測試通過

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class getmac{
public static String getLinuxMACAddress() {
        String mac = null;
        BufferedReader bufferedReader = null;
        Process process = null;
        try {            
            process = Runtime.getRuntime().exec("ifconfig enp4s0");
            bufferedReader = new BufferedReader(new InputStreamReader(
                    process.getInputStream()));
            String line = null;
            int index = -1;
            while ((line = bufferedReader.readLine()) != null) {
                index = line.toLowerCase().indexOf("硬件地址");
                
                if (index != -1) {
                    
                    mac = line.substring(index + 4).trim();
                    break;
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedReader != null) {
                    bufferedReader.close();
                }
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            bufferedReader = null;
            process = null;
        }
        return mac;
    }
public static void main(String[] argc) {
    String mac = getLinuxMACAddress();
    System.out.println("本地是Linux系統, MAC地址是:" + mac);

}
}

　　運行結果如下：

本地是Linux系統, MAC地址是:54:ab:3a:05:34:e6

　　通過最近幾周的經歷發現，網上的東西都是僅供參考，因為環境的不同、版本的不同會造成很大的差異，而且很多人都只是轉載，從未驗證，告誡自己無論任何東西，一定要切身驗證，

　　也要養成寫博客的習慣，把自己的過程記錄記載下來，供別人和自己以后參考。