java 随机获取Mac地址

public String getMac() {
StringBuffer mac = new StringBuffer();
for(int i=1; i<=6; i++) {
String one = getStringRandom(1);
String two = getStringRandom(1);
mac.append(one).append(two);
if(i != 6) mac.append(":");
}
return mac.toString().toLowerCase();
}
//生成随机数字和字母,
public String getStringRandom(int length) {
String val = "";
Random random = new Random();
//参数length，表示生成几位随机数
for(int i = 0; i < length; i++) {
String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
//输出字母还是数字
if( "char".equalsIgnoreCase(charOrNum) ) {
//输出是大写字母还是小写字母
int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
val += (char)(random.nextInt(6) + temp);
} else if( "num".equalsIgnoreCase(charOrNum) ) {
val += String.valueOf(random.nextInt(10));
}
}
return val;
}