集合比较
List<Map.Entry<Integer, Integer>> infoIds = new ArrayList<Map.Entry<Integer, Integer>>(
map.entrySet());

Collections.sort(infoIds, new Comparator<Map.Entry<Integer, Integer>>()
{
public int compare(Map.Entry<Integer, Integer> o1,
Map.Entry<Integer, Integer> o2)
{
return (o1.getKey() - o2.getKey()); //升序
}
});