生成随机数并在Redis中存储

 

/**
 * 生成 num 位随机码
 *
 * @param num 位数
 * @return String
 */
public static String randomCode(int num) {
    StringBuilder builder = new StringBuilder();
    Random random = new Random();
    for (int i = 0; i < num; i++) {
        builder.append(random.nextInt(10));
    }
    return builder.toString();
}

public static final String REDIS_STUDENT_KEY = "jq:ms:m:";
@Autowired
private StringRedisTemplate stringRedisTemplate;

 

// 生产六位唯一码
Set<String> randCodes = stringRedisTemplate.opsForSet().members(REDIS_STUDENT_KEY + missionId);
String randCode;
while (true) {
    randCode = NumberUtils.randomCode(4);
    // Set 中不存在 randCode
    if (randCodes == null || !randCodes.contains(randCode)) {
        // 当前时间，缓存中不存在 randCode
        Boolean isMember = stringRedisTemplate.opsForSet().isMember(REDIS_STUDENT_KEY + missionId, randCode);
        if (isMember == null || !isMember) {
            break;
        }
    }
}