int number = -1;
    int holdingDigits = 7;
    System.out.println(String.format("%0"+ holdingDigits +"d", number));

刚刚在采访中问过这个问题........

我的答案如下，但这个(上面提到的)要好得多——>

管柱。format(“% 05d”,全国矿工工会);

我的回答是:

static String leadingZeros(int num, int digitSize) {
    //test for capacity being too small.

    if (digitSize < String.valueOf(num).length()) {
        return "Error : you number  " + num + " is higher than the decimal system specified capacity of " + digitSize + " zeros.";

        //test for capacity will exactly hold the number.
    } else if (digitSize == String.valueOf(num).length()) {
        return String.valueOf(num);

        //else do something here to calculate if the digitSize will over flow the StringBuilder buffer java.lang.OutOfMemoryError 

        //else calculate and return string
    } else {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < digitSize; i++) {
            sb.append("0");
        }
        sb.append(String.valueOf(num));
        return sb.substring(sb.length() - digitSize, sb.length());
    }
}

使用谷歌番石榴:

Maven:

<dependency>
     <artifactId>guava</artifactId>
     <groupId>com.google.guava</groupId>
     <version>14.0.1</version>
</dependency>

示例代码:

Strings.padStart("129018", 10, '0') returns "0000129018"  

如果你的字符串只包含数字，你可以让它成为一个整数，然后做填充:

String.format("%010d", Integer.parseInt(mystring));

如果没有，我想知道如何才能做到。

如果你需要性能并且知道字符串的最大大小，使用以下方法:

String zeroPad = "0000000000000000";
String str0 = zeroPad.substring(str.length()) + str;

注意最大字符串大小。如果它大于StringBuffer的大小，你会得到一个java.lang.StringIndexOutOfBoundsException。

    int number = -1;
    int holdingDigits = 7;
    System.out.println(String.format("%0"+ holdingDigits +"d", number));

刚刚在采访中问过这个问题........

我的答案如下，但这个(上面提到的)要好得多——>

管柱。format(“% 05d”,全国矿工工会);

我的回答是:

static String leadingZeros(int num, int digitSize) {
    //test for capacity being too small.

    if (digitSize < String.valueOf(num).length()) {
        return "Error : you number  " + num + " is higher than the decimal system specified capacity of " + digitSize + " zeros.";

        //test for capacity will exactly hold the number.
    } else if (digitSize == String.valueOf(num).length()) {
        return String.valueOf(num);

        //else do something here to calculate if the digitSize will over flow the StringBuilder buffer java.lang.OutOfMemoryError 

        //else calculate and return string
    } else {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < digitSize; i++) {
            sb.append("0");
        }
        sb.append(String.valueOf(num));
        return sb.substring(sb.length() - digitSize, sb.length());
    }
}

右填充固定长度-10: 字符串。格式(“% 1 $ -10年代”,“abc”) 左填充固定长度-10: 字符串。格式(“% 1 $ 10 s”、“abc”)