//LinkedHashMap先入先出

public class Test {public static void main(String[] args) {Map
     
       map = new HashMap
      
       ();map.put("aaa", "111");map.put("bbb", "222");map.put("ccc", "333");for(Entry
       
         e :map.entrySet()){System.out.println("key:"+e.getKey()+",value:"+e.getValue());}} public static void main_1(String[] args) {   LinkedHashMap
        
          map = new LinkedHashMap
         
          ();  map.put("1", "one");   map.put("2", "tow");  map.put("3", "three");  for(Entry
          
            e: map.entrySet()){ System.out.println(e.getKey()+":"+e.getValue()); } } }