Javaにおけるmapの3つの遍歴方式

1305 ワード

public class Test {



    public static void main(String[] args) {
        Map map = new HashMap<>();
        map.put(1,"a");
        map.put(2,"b");
        map.put(3,"c");

        //       :  key
        System.out.println("       :  key");
        Set keySet = map.keySet();
        for (Integer key:keySet) {
            System.out.println(key+" "+map.get(key));
        }
        //       :  value
        System.out.println("       :  value");
        Set> entrySet = map.entrySet();
        for (Map.Entry entry:entrySet){
            System.out.println(entry.getKey()+" "+entry.getValue());
        }
        //       :Iterator(            )
        System.out.println("       :Iterator(            )");
        Iterator> it = map.entrySet().iterator();
        while(it.hasNext()){
            Map.Entry entry = it.next();
            System.out.println(entry.getKey()+" "+entry.getValue());
        }

        //         values
        map.values();
        for (String value:map.values()) {
            System.out.println(value);
        }

    }

    
}