HashMap 정렬

HashMap key순서로 정렬하기.




import java.util.Collections;

import java.util.HashMap;

import java.util.Iterator;

import java.util.TreeMap;

 

public class MapSort {

 

    public static void main(String[] args){

 

        HashMap<String, String> hashMap  = new HashMap<String, String>();

 

        hashMap.put("test3", "name5");

        hashMap.put("test4", "name2");

        hashMap.put("test5", "name1");

        hashMap.put("test1", "name3");

        hashMap.put("test2", "name4");

         

        System.out.println("==========오름차순============");

        //오름차순

        TreeMap<String, String> treeMap = new TreeMap<String, String>( hashMap );

        Iterator<String> treeMapIter = treeMap.keySet().iterator();

 

        while( treeMapIter.hasNext()) {

 

            String key = treeMapIter.next();

            String value = treeMap.get( key );

 

            System.out.println(key+" : "+value);

 

        }

 

        System.out.println("==========내림차순============");

        //내림차순

        TreeMap<String, String> treeMapReverse = new TreeMap<String, String>(Collections.reverseOrder());

        treeMapReverse.putAll(hashMap);

 

        Iterator<String> treeMapReverseIter = treeMapReverse.keySet().iterator();

 

        while( treeMapReverseIter.hasNext()) {

 

            String key = treeMapReverseIter.next();

            String value = treeMapReverse.get( key );

 

            System.out.println(key+" : "+value);

 

        }

 

    }

 

}

출처 : http://huskdoll.tistory.com/5