增量后将整数零填充为字符串

Question

我需要增加一个只有数字的字符串：

String current = "000433"; //After increment, will be "000434"

我有这个程序，它正常工作：

private String incrementOne(String numberAsString) {
    int leftZeroCount = countLeadingZeros(numberAsString);
    Integer asInteger = Integer.parseInt(numberAsString);
    asInteger++;
    return parseStringWithNZeros(asInteger, leftZeroCount);
}

private String parseStringWithNZeros(Integer asInteger, int leftZeroCount) {
    String asString = Integer.toString(asInteger);
    for (int i = 0; i < leftZeroCount; i++)
        asString = "0" + asString;
    return asString;
}

private int countLeadingZeros(String numberAsString) {
    int count = 0;
    int i = 0;
    while (numberAsString.charAt(i) == '0' && i < numberAsString.length()) {
        count++;
        i++;
    }
    return count;
}

过程是：

1. 计算左边的零
2. Parse to Integer
3. 增加一个
4. Parse to String
5. 添加左边的零

String的数字长度未知。我确信存在另一种更容易和更清洁的方式，使用正则表达式或其他东西。我可以采用哪些替代方案？

感谢。

Answer 1

如何使用String.format()：

这样做

String original = "000433";
String incremented = String.format("%0" + original.length() + "d",
            Integer.parseInt(original) + 1);

System.out.println(incremented);

Answer 2

试试这个：

private String incrementOne(String numberAsString) {
   int length = numberAsString.length();
   Integer asInteger = Integer.parseInt(numberAsString);
   asInteger++;
   numberAsString = asInteger.toString();
   while(numberAsString.length() < length){
      numberAsString = "0" + numberAsString;
      count ++;
   }
   return numberAsString;
}