1 Map
     
       map = new HashMap
      
       (); 2         map.put(1, "a"); 3         map.put(2, "b"); 4          5         System.out.println("(1):"); 6         //1.Map输出1(只遍历一次,速度快) 7         Iterator itr11 = map.entrySet().iterator(); 8         while(itr11.hasNext()){ 9             Map.Entry e = (Map.Entry)itr11.next();10             System.out.println(e.getKey()+"==="+e.getValue());11         }12         System.out.println();13         System.out.println("(2):");14         //2.Map输出2（速度慢）15         Set set = map.keySet();//用接口实例接口16         Iterator itr22 = set.iterator();17         while(itr22.hasNext()){
   //遍历二次,速度慢18             Integer key = (Integer)itr22.next();19             System.out.println(key+"==="+map.get(key));20         }21         //3.Map输出3（for语句）22         System.out.println();23         System.out.println("(3):");24         Set
       
         set00 = map.keySet();25         for(Integer s :set00){26             System.out.println(s+"==="+map.get(s));27         }28         29         //4.Map输出430         System.out.println();31         System.out.println("(4):");32         Iterator itr44 = map.values().iterator();        33         while(itr44.hasNext()){34             System.out.println(itr44.next());35         }36         System.out.println();37         38         //5.Map输出539         System.out.println("(5):");40         System.out.println(map);41         42         //6.Map输出643         System.out.println();44         System.out.println("(6):");45         for(Map.Entry en:map.entrySet()){46             System.out.println(en.getKey()+"==="+en.getValue());47         }
       
      
     

 

输出：