按键和值对地图排序

import java.util.SortedSet;import java.util.TreeSet;public class SortMaponKeyAndValue {    public static void main(String[] args) {        SortedSet<KeyValuePair> sortedSet = new TreeSet<KeyValuePair>();        sortedSet.add(new KeyValuePair(1, 2));        sortedSet.add(new KeyValuePair(2, 2));        sortedSet.add(new KeyValuePair(1, 3));        sortedSet.add(new KeyValuePair(2, 1));        for (KeyValuePair keyValuePair : sortedSet) { System.out.println(keyValuePair.key+","+keyValuePair.value);        }    }}class KeyValuePair implements Comparable<KeyValuePair>{    int key, value;    public KeyValuePair(int key, int value) {        super();        this.key = key;        this.value = value;    }    public int compareTo(KeyValuePair o) {        return key==o.key?value-o.value:key-o.key;    }}