SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmsSSSS");

long seed = System.currentTimeMillis();// 獲得系統時間，作為生成隨機數的種子

Random random = new Random(seed);// 呼叫種子生成隨機數

StringBuffer randomString = new StringBuffer();// 裝載生成的隨機數

for(int index = 0; index < 20; index ++){

    randomString.append(charArray.charAt(random.nextInt(charLen)));

}

String result = sdf.format(new Date()) + randomString;

return result ;