java - 取消格式化字符串

Question

我有一个简单的格式化字符串:

double d = 12.348678;
int i = 9876;
String s = "ABCD";
System.out.printf("%08.2f%5s%09d", d, s, i);

// %08.2f = '12.348678' -> '00012,35'
// %5s = 'ABCD' -> ' ABCD'
// %09d = '9876' -> '000009876'
// %08.2f%5s%09d = '00012,35 ABCD000009876'

当我知道模式:%08.2f%5s%09d和字符串:00012,35 ABCD000009876时:我可以以某种方式“取消格式化”这个字符串吗？

例如。预期结果类似于 3 个标记:'00012,35'、'ABCD'、'000009876'

Answer 1

这特定于您的模式。格式字符串的通用解析器(因为我们所说的取消格式化就是解析)看起来会有很大不同。

public class Unformat {

    public static Integer getWidth(Pattern pattern, String format) {
        Matcher matcher = pattern.matcher(format);
        if (matcher.find()) {
            return Integer.valueOf(matcher.group(1));
        }
        return null;
    }

    public static String getResult(Pattern p, String format, String formatted,
            Integer start, Integer width) {
        width = getWidth(p, format);
        if (width != null) {
            String result = formatted.substring(start, start + width);
            start += width;
            return result;
        }
        return null;
    }

    public static void main(String[] args) {
        String format = "%08.2f%5s%09d";
        String formatted = "00012.35 ABCD000009876";
        String[] formats = format.split("%");

        List<String> result = new ArrayList<String>();
        Integer start = 0;
        Integer width = 0;

        for (int j = 1; j < formats.length; j++) {
            if (formats[j].endsWith("f")) {
                Pattern p = Pattern.compile(".*([0-9])+\\..*f");
                result.add(getResult(p, formats[j], formatted, start, width));
            } else if (formats[j].endsWith("s")) {
                Pattern p = Pattern.compile("([0-9])s");
                result.add(getResult(p, formats[j], formatted, start, width));
            } else if (formats[j].endsWith("d")) {
                Pattern p = Pattern.compile("([0-9])d");
                result.add(getResult(p, formats[j], formatted, start, width));
            }
        }
        System.out.println(result);
    }

}