java - 如何克服freemarker树集按字母顺序排序int键？

Question

我有一个树集。

字符串键实际上是一个 int 的字符串值，因为 freemarker 不允许 int 作为映射的键，并且由于这是一个排序的映射，它对它的排序如下：

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

任何人都知道如何解决这个问题并使其按数字顺序打印？

谢谢

Answer 1

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.)

Answer 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));
  }
});