关于判断无限大数字字符串能否被6整除问题的解决方法

import java.util.Random;

 

public class TestBigString {

 /**
  * @param args
  */
 public void test(String s) {//将字符串转化成数组
  char[] a = s.toCharArray();
  test1(a);
 }

 public void test1(char[] a) {
  int temp1 = 0;
  String tem="";
  for (char c : a) {//便利数组从高位开始 对6取余数，然后余数*10+下一位继续相同操作
   tem = String.valueOf(c);
   temp1 = temp1 * 10 + Integer.parseInt(tem);
   temp1 = temp1 % 6;
  }
  if (temp1 != 0) {//判断余数 如果是0 能整除
   System.out.println("不能被6整除");
  } else
   System.out.println("能被6整除");
 }

 public static StringBuffer generate() {
  StringBuffer bf=new StringBuffer();
  for (long i = 0; i < 10000000; i++) {
   Random rand = new Random();
   int temp = rand.nextInt(10);
   bf.append(temp);
  }
  return bf;
 }

 public static void main(String[] args) {
  // System.out.println(Long.parseLong(s)%6);
  Long a = System.currentTimeMillis();
  String s = TestBigString.generate().toString();
  Long b = System.currentTimeMillis();
  System.out.println(b-a);//测试 时间
  System.out.println(s.length());
  TestBigString tbs = new TestBigString();
  Long c = System.currentTimeMillis();
  tbs.test(s);
  Long e = System.currentTimeMillis();
  System.out.println(e-c);//测试计算用的时间2-3秒
 }
}