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2017.07.05 / 02:24

[Java] HashMap Value 정렬

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[Java] HashMap Value 정렬


import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
  
  
public class Test {
  
    public static void main(String[] args) {
        Map<string,integer> map = new HashMap<string,integer>();
        map.put("a",3);
        map.put("b",2);
        map.put("c",1);
         
        System.out.println("------------sort 전 -------------");
        System.out.println(map);
         
        Iterator it = Test.sortByValue(map).iterator();
         
         
        System.out.println("---------sort 후------------");
        while(it.hasNext()){
            String temp = (String) it.next();
            System.out.println(temp + " = " + map.get(temp));
        }
        //System.out.println(map);
    }
     
    public static List sortByValue(final Map map){
        List<string> list = new ArrayList();
        list.addAll(map.keySet());
         
        Collections.sort(list,new Comparator(){
             
            public int compare(Object o1,Object o2){
                Object v1 = map.get(o1);
                Object v2 = map.get(o2);
                 
                return ((Comparable) v1).compareTo(v2);
            }
             
        });
        Collections.reverse(list); // 주석시 오름차순
        return list;
    }
}
</string></string,integer></string,integer>


출처: http://ekfqkqhd.tistory.com/entry/Java-HashMap-Value-정렬 [시우아빠님의 블로그]