Map迭代（六种）

Map<Integer,String> map = new HashMap<Integer,String>();
        map.put(1, "a");
        map.put(2, "b");
        
        System.out.println("(1):");
        //1.Map输出1(只遍历一次,速度快)
        Iterator itr11 = map.entrySet().iterator();
        while(itr11.hasNext()){
            Map.Entry e = (Map.Entry)itr11.next();
            System.out.println(e.getKey()+"==="+e.getValue());
        }
        System.out.println();
        System.out.println("(2):");
        //2.Map输出2（速度慢）
        Set set = map.keySet();//用接口实例接口
        Iterator itr22 = set.iterator();
        while(itr22.hasNext()){//遍历二次,速度慢
            Integer key = (Integer)itr22.next();
            System.out.println(key+"==="+map.get(key));
        }
        //3.Map输出3（for语句）
        System.out.println();
        System.out.println("(3):");
        Set<Integer> set00 = map.keySet();
        for(Integer s :set00){
            System.out.println(s+"==="+map.get(s));
        }
        
        //4.Map输出4
        System.out.println();
        System.out.println("(4):");
        Iterator itr44 = map.values().iterator();        
        while(itr44.hasNext()){
            System.out.println(itr44.next());
        }
        System.out.println();
        
        //5.Map输出5
        System.out.println("(5):");
        System.out.println(map);
        
        //6.Map输出6
        System.out.println();
        System.out.println("(6):");
        for(Map.Entry en:map.entrySet()){
            System.out.println(en.getKey()+"==="+en.getValue());
        }

输出：