Java--map的遍历方式

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
public class map {
    public static void main(String[] args) {
        Map<String,String> map = new HashMap() {};
        System.out.println(map.put("a","1"));
        map.put("b","2");
        map.put("c","3");

        for (Map.Entry<String,String> entry:map.entrySet()){
            System.out.println(entry.getKey());
            System.out.println(entry.getValue());
        }
        System.out.println("***********************");
        for (String key:map.keySet()){
            System.out.println(key);
        }
        System.out.println("***********************");
        Iterator<Map.Entry<String,String>> iterator = map.entrySet().iterator();
        while (iterator.hasNext()){
            Map.Entry<String,String> item = iterator.next();
            System.out.println(item.getKey()+"---"+item.getValue());
        }
        System.out.println("***********************");
        for (String string:map.values()){
            System.out.println(string);
        }


    }
}