高级for循环

import java.util.*;
class Test{
    public static void main(String[] args){
        ArrayList<String> al1=new ArrayList<>();
        al1.add("abc1");
        al1.add("abc2");
        al1.add("abc3");
        /*
        Iterator<String> it=al1.iterator();
        while (it.hasNext()){
            sop(it.next());
        }
        */
        for (String s:al1){//底层原理还是迭代器,简化书写
            sop(s);
        }
        HashMap<Integer,String> hm=new HashMap<>();
        hm.put(1,"a");
        hm.put(2,"b");
        hm.put(3,"c");
        //Set<Map.Entry<Integer,String>> entrySet1=hm.entrySet();
      //for(Map.Entry<Integer,String> me:entrySet1){}
        for(Map.Entry<Integer,String> me:hm.entrySet()){
            sop(me.getKey()+"---"+me.getValue());
        }
    }
    public static void sop(Object obj){
        System.out.println(obj);
    }
}