code: public static long nextLong(Random random) {
  		long n = random.nextLong();
  		if (n == Long.MIN_VALUE) {
  			n = 0; // corner case
  		} else {
  			n = Math.abs(n);
  		}
  		return n;
  	}
docs: 返回0－Long.MAX_VALUE间的随机Long, 可传入SecureRandom或ThreadLocalRandom