Java Map을 iteration 시키는 세 가지 방법.

Three way to iterate Java Map.

import java.util.Map;

public class MapTest{
    public static void main(String[] args){
        Map map = new HashMap();

        map.put("key1", "value1");
        map.put("key2", "value2");
        map.put("key3", "value3");
        map.put("key4", "value4");
        map.put("key5", "value5");

        // solution 1
        Iterator keys = map.keySet().iterator();
        while(keys.hasNext()){
            String key = keys.next();
            System.out.println("key: " + key + ", value: " + map.get(key));
        }

        // solution 2
        for( Map.Entry elem : map.entrySet() ){
            System.out.println( String.format("key : %s, value : %s", elem.getKey(), elem.getValue()) );
        }
        
        // solution 3
        for( String key : map.keySet() ){
            System.out.println( String.format("key : %s, value : %s", key, map.get(key)) );
        }
    }
}