数字前面填充0工具类

工具类

public class ParamUtil {
          
   

    //检查是否为数字
    private static final Pattern pattern = Pattern.compile("[0-9]*");
    //检查是否为01-99之间的数字
    private static final Pattern pattern2 = Pattern.compile("^([1-9]|0[1-9]|[1-9][0-9])$");
    //检查是否大于0小于等于100的整数
    private static final Pattern pattern1 = Pattern.compile("^100$|^([1-9]|[1-9]\d)$");

    public static <T> ReqBody<T> checkRequest(ReqBody<T> reqBody) {
          
   
        if (reqBody == null) {
          
   
            throw new GlobalErrorInfoException(StockErrorInfoEnum.REQBODY_EMPTY);
        }
        if (reqBody.getParam() == null) {
          
   
            throw new GlobalErrorInfoException(StockErrorInfoEnum.PARAM_EMPTY);
        }
        return reqBody;
    }

    /**
     * 填充0
     *
     * @param number      需要填充的数
     * @param totalDigits 填充的总位数
     * @return
     */
    public static String filling(String number, Integer totalDigits) {
          
   
        boolean flag = StringUtils.isEmpty(number) && (null == totalDigits || totalDigits < 2);
        if (flag) {
          
   
            return null;
        }
        String newNumBer = number;
        int length = newNumBer.length();
        if (length < totalDigits) {
          
   
            for (int i = 1; i <= totalDigits - length; i++) {
          
   
                newNumBer = "0".concat(newNumBer);
            }
        }
        return newNumBer;
    }

    /**
     * 检查字符串是否为数字
     *
     * @param str
     * @return
     */
    public static boolean checkStrIsNum(String str) {
          
   

        if(StringUtils.isBlank(str)){
          
   
            return true;
        }

        Matcher isNum = pattern2.matcher(str);
        return isNum.matches();
    }

    /**
     * 检查字符是否为大于0小于等于100
     *
     * @param smartPi
     * @return
     */
    public static boolean checkSmartPi(String smartPi) {
          
   

        if(StringUtils.isBlank(smartPi)){
          
   
            return true;
        }
        Matcher isNum = pattern1.matcher(smartPi);
        return isNum.matches();
    }
}

调用示例：

/* 前面补0，凑成2位数。如：9补0后是：09 */
String department = ParamUtil.filling(department2, 2);