How to overcome freemarker treeset sorting int keys alphabetically?

Question

I have a TreeSet.

The string key is actually a string value of an int, as freemarker doesn't allow ints as keys to maps, and as this is a sorted map, it sorts it as below:

1
10
11
12
2
3
4
5
6
7
8
9

Anyone know how to get around this and make it print in numerical order?

Thanks

http://stackoverflow.com/a/7227772/681807 – My Head Hurts Sep 03 '12 at 18:07 — My Head Hurts, Sep 03 '12 at 18:07
http://stackoverflow.com/a/9556369/681807 – My Head Hurts Sep 03 '12 at 18:07 — My Head Hurts, Sep 03 '12 at 18:07

Dave Newton · Answer 1 · 2012-09-03T18:21:56.137

2

Construct the map with an appropriate comparator via the constructor TreeMap(Comparator).

(Or TreeSet, if that's what you actually mean; you mention both sets and maps.)

edited Sep 03 '12 at 18:21

answered Sep 03 '12 at 18:07

Dave Newton

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obataku · Accepted Answer · 2012-09-03T18:18:08.960

2

String internally imposes a lexicographic order via compareTo.

Compares two strings lexicographically.

If you don't want that, consider specifying a custom Comparator e.g.

final Map<String, ...> map = new TreeMap<String, ...>(new Comparator<String>() {

  public int compare(final String a, final String b) {
    return Integer.valueOf(a).compareTo(Integer.valueOf(b));
  }
});

edited Sep 03 '12 at 18:18

answered Sep 03 '12 at 18:08

obataku

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How to overcome freemarker treeset sorting int keys alphabetically?

2 Answers2