获取Android设备无线和以太网MAC地址

package com.raycloud.wolf.blogformac;

import android.net.wifi.WifiManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

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

public class MainActivity extends AppCompatActivity {

    private final String tag = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.wifiMacButton).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                WifiManager wifiManager = (WifiManager) getApplicationContext().getSystemService(WIFI_SERVICE);
                Log.d(tag, "WiFi MAC Address: " + wifiManager.getConnectionInfo().getMacAddress());
            }
        });
        findViewById(R.id.ethernetMacButton).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try (BufferedReader input = new BufferedReader(new InputStreamReader(new FileInputStream("/sys/class/net/eth0/address")))) {
                    String ethernetMacAddress = input.readLine();
                    Log.d(tag, "Ethernet MAC Address: " + ethernetMacAddress);
                } catch (IOException ex) {
                    Log.e(tag, "ex: " + ex);
                }
            }
        });
    }
}