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copied!<p>I don't know of a library that does that. Here is an example how to convert a format pattern into a regex. Notice that <code>Pattern.quote</code> is important to handle accidental regexes in the format string.</p> <pre><code>// copied from java.util.Formatter // %[argument_index$][flags][width][.precision][t]conversion private static final String formatSpecifier = "%(\\d+\\$)?([-#+ 0,(\\<]*)?(\\d+)?(\\.\\d+)?([tT])?([a-zA-Z%])"; private static final Pattern formatToken = Pattern.compile(formatSpecifier); public Pattern convert(final String format) { final StringBuilder regex = new StringBuilder(); final Matcher matcher = formatToken.matcher(format); int lastIndex = 0; regex.append('^'); while (matcher.find()) { regex.append(Pattern.quote(format.substring(lastIndex, matcher.start()))); regex.append(convertToken(matcher.group(1), matcher.group(2), matcher.group(3), matcher.group(4), matcher.group(5), matcher.group(6))); lastIndex = matcher.end(); } regex.append(Pattern.quote(format.substring(lastIndex, format.length()))); regex.append('$'); return Pattern.compile(regex.toString()); } </code></pre> <p>Of course, implementing <code>convertToken</code> will be a challenge. Here is something to start with:</p> <pre><code>private static String convertToken(String index, String flags, String width, String precision, String temporal, String conversion) { if (conversion.equals("s")) { return "[\\w\\d]*"; } else if (conversion.equals("d")) { return "[\\d]{" + width + "}"; } throw new IllegalArgumentException("%" + index + flags + width + precision + temporal + conversion); } </code></pre>

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