Map的使用方式--iterator collections的使用

1 iteratorlai  来循环

      1.1

 public static void main(String[] args) {
  // TODO Auto-generated method stub
  Map map = new HashMap();
  map.put("drink", "1");
  map.put("hello", "3");
  map.put("food", "2");
  Iterator iterator = map.keySet().iterator();
  while(iterator.hasNext()){
   System.out.println(map.get(iterator.next()));
  }

}

 

1.2

      Set entries = map.entrySet( );
  Iterator iterator = entries.iterator( );
  while(iterator.hasNext( )) {
   Map.Entry entry =(Map.Entry)iterator.next();
   Object key = entry.getKey( );
   Object value = entry.getValue();
   System.out.println("Key:"+key);
   System.out.println("/n"+entry); //food=2
  }

       

 

2 Collections 得到最大最小值

 

  Collection collection = map.values();//返回数值

 

Set sets= map.keySet();
System.out.println(Collections.max(sets));//key的最大值

 

Collection collection = map.values();

System.out.println(Collections.max(collection));//value的最大值