java中实现HashMap中的按照key的字典顺序排序输出

关键代码

 HashMap<String, String> maptest =new  HashMap<String, String>();
		 maptest.put("1天","day1");
		 maptest.put("5天","day5");
		 maptest.put("4天","day4");
		 maptest.put("2天","day2");
		 maptest.put("3天","day3");
		 
		 Collection<String> keyset= maptest.keySet();
		 List<String> list = new ArrayList<String>(keyset);
		 
		 //对key键值按字典升序排序
		 Collections.sort(list);
		 
		 
		 for (int i = 0; i < list.size(); i++) {
			 System.out.println("key键---值: "+list.get(i)+","+maptest.get(list.get(i)));
		 }