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copied!<p>//the fishing technique</p> <pre><code>List<String> values = new ArrayList<String>(); values.add("AB"); values.add("A012B"); values.add("CD"); values.add("1"); values.add("10"); values.add("01"); values.add("9"); values.add("I"); Collections.sort(values, new Comparator<String>() { @Override public int compare(String o1, String o2) { // TODO tweak the comparator here try{ Integer integer1 = Integer.valueOf(o1); Integer integer2 = Integer.valueOf(o2); return integer1.compareTo(integer2); }catch (java.lang.NumberFormatException e) { return o1.compareTo(o2); } } }); System.out.println(values); } </code></pre> <p>//not enough???</p> <p>//here is the fish</p> <pre><code>public static void main(String[] args) throws Exception { List<String> values = new ArrayList<String>(); values.add("AB"); values.add("A012B"); values.add("CD"); values.add("1"); values.add("10"); values.add("01"); values.add("9"); int maxLen = 0; for (String string : values) { if (string.length() > maxLen) { maxLen = string.length(); } } Collections.sort(values, new MyComparator(maxLen)); System.out.println(values); } public static class MyComparator implements Comparator<String> { private int maxLen; private static final String REGEX = "[0-9]+"; public MyComparator(int maxLen) { this.maxLen = maxLen; } @Override public int compare(String obj1, String obj2) { String o1 = obj1; String o2 = obj2; // both numbers if (o1.matches("[1-9]+") && o2.matches("[1-9]+")) { Integer integer1 = Integer.valueOf(o1); Integer integer2 = Integer.valueOf(o2); return integer1.compareTo(integer2); } // both string if (o1.matches("[a-zA-Z]+") && o2.matches("[a-zA-Z]+")) { return o1.compareTo(o2); } Pattern p = Pattern.compile(REGEX); Matcher m1 = p.matcher(o1); Matcher m2 = p.matcher(o2); List<String> list = new ArrayList<String>(); while (m1.find()) { list.add(m1.group()); } for (String string : list) { o1.replaceFirst(string, leftPad(string, "0", maxLen)); } list.clear(); while (m2.find()) { list.add(m2.group()); } for (String string : list) { o2.replaceFirst(string, leftPad(string, "0", maxLen)); } return o1.compareTo(o2); } } public static String leftPad(String stringToPad, String padder, Integer size) { final StringBuilder strb = new StringBuilder(size.intValue()); final StringCharacterIterator sci = new StringCharacterIterator(padder); while (strb.length() < (size.intValue() - stringToPad.length())) { for (char ch = sci.first(); ch != CharacterIterator.DONE; ch = sci.next()) { if (strb.length() < (size.intValue() - stringToPad.length())) { strb.insert(strb.length(), String.valueOf(ch)); } } } return strb.append(stringToPad).toString(); } </code></pre>

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