http://blog.youkuaiyun.com/RabbitEatPumpkin/article/details/4730544 今天迭代hashmap时,hashmap并不能按照put的顺序,迭代输出值。用下述方法可以: HashMap<String,String> hashmap = new LinkedHashMap<String,String>(); HashSet的内容如何排序 HashSet和TreeSet