Java implements a simple code to randomly generate mobile phone SMS verification codes

This article mainly introduces the method of randomly generating mobile phone SMS verification codes in Java, involving Java mathematical operations and related techniques of calculating random numbers and string operations. It has certain reference value. Friends in need can refer to it

The example of this article describes the method of randomly generating mobile phone SMS verification codes in Java. Share it with everyone for your reference, the details are as follows:

/**
* 创建指定数量的随机字符串
* @param numberFlag 是否是数字
* @param length
* @return
*/
public static String createRandom(boolean numberFlag, int length){
 String retStr = "";
 String strTable = numberFlag ? "1234567890" : "1234567890abcdefghijkmnpqrstuvwxyz";
 int len = strTable.length();
 boolean bDone = true;
 do {
  retStr = "";
  int count = 0;
  for (int i = 0; i < length; i++) {
  double dblR = Math.random() * len;
  int intR = (int) Math.floor(dblR);
  char c = strTable.charAt(intR);
  if ((&#39;0&#39; <= c) && (c <= &#39;9&#39;)) {
   count++;
  }
  retStr += strTable.charAt(intR);
  }
  if (count >= 2) {
  bDone = false;
  }
 } while (bDone);
 return retStr;
}

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