package cn.vicky.vo; import java.util.Comparator; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.TreeMap; public class MyIntComparator implements Comparator<Integer> { public int compare(Integer o1, Integer o2) { // 倒序 if (o1 > 02) { return -1; } else if (o1 < o2) { return 1; } return 0; } public static void outMap(Map map) { if (map != null) { Iterator<Integer> keys = map.keySet().iterator(); Iterator<String> values = map.values().iterator(); while (keys.hasNext()) { System.out.println("key[" + keys.next() + "] value[" + values.next() + "]"); } } } public static void main(String[] args) { Map<Integer, String> myMap = new HashMap<Integer, String>(); myMap.put(4, "d"); myMap.put(1, "a"); myMap.put(5, "e"); myMap.put(3, "c"); myMap.put(6, "f"); myMap.put(2, "b"); outMap(myMap); System.out.println("----------"); TreeMap<Integer, String> myTreeMap = new TreeMap<Integer, String>(new MyIntComparator()); myTreeMap.putAll(myMap); outMap(myTreeMap); } }

列印：

key[1]  value[a]
key[2]  value[b]
key[3]  value[c]
key[4]  value[d]
key[5]  value[e]
key[6]  value[f]
----------
key[6]  value[f]
key[5]  value[e]
key[4]  value[d]
key[3]  value[c]
key[1]  value[b]