• Random是线程安全的
  • ThreadLocalRandom在高并发场景下建议使用

    Random实现短信验证码

    ```java
  1. public static void main(String[] args) {
  2.     System.out.println(verificationCode(8));
  3.     System.out.println(randomPassword(8));
  4. }
  6. /**
  7.  * 生产随机验证码
  8.  */
  9. public static String verificationCode(int length) {
  10.     if (4 != length & 6 != length & 8 != length) {
  11.         throw new RuntimeException("错误");
  12.     }
  13.     char[] chars = new char[length];
  14.     Random random = new Random();
  15.     for (int i = 0; i < length; i++) {
  16.        chars[i] = (char) ('0' + random.nextInt(10));
  17.     }
  18.     return new String(chars);
  19. }
  23. private static final String SPECIAL_CHARS = "!@#$%^&*/|";
  24. /**
  25.  * 生产随机字符
  26.  * @param random
  27.  * @return
  28.  */
  29. public static char nextChar(Random random){
  30.     switch (random.nextInt(4)){
  31.         case 0 :
  32.             return (char) ('0' + random.nextInt(10));
  33.         case 1 :
  34.             return (char) ('A' + random.nextInt(26));
  35.         case 2 :
  36.             return (char) ('a' + random.nextInt(26));
  37.         default: return SPECIAL_CHARS.charAt(random.nextInt(SPECIAL_CHARS.length()));
  38.     }
  39. }
  41. /**
  42.  * 生产随机密码
  43.  * 密码长度最好12位
  44.  * @param length
  45.  * @return
  46.  */
  47. public static String randomPassword(int length){
  48.     if (6 > length){
  49.         throw new RuntimeException("密码长度必须为六位以上");
  50.     }
  51.     char[] chars = new char[length];
  52.     ThreadLocalRandom random = ThreadLocalRandom.current();
  53.     for (int i = 0; i < length; i++) {
  54.         chars[i] = nextChar(random);
  55.     }
  56.     return new String(chars);
  57. }

```

ThreadLocalRandom实现随机密码