public void statisticsA(){ List<Moves> file = this.file(); Map<String,Integer> map = new HashMap<>(); int init=1; for (Moves moves1 : file) { if("".equals(moves1.getDate())||moves1.getDate()==null){ continue; } if(map.containsKey(moves1.getDate())){ Integer count = map.get(moves1.getDate()); map.put(moves1.getDate(),++count); }else{ map.put(moves1.getDate(),init); } } ArrayList<Map.Entry<String, Integer>> entries = new ArrayList<>(map.entrySet()); Collections.sort(entries,new Comparator<Map.Entry<String, Integer>>(){ @Override public int compare(Map.Entry<String, Integer> v1, Map.Entry<String, Integer> v2) { return Integer.valueOf(v1.getKey()) - Integer.valueOf(v2.getKey()); } }); Iterator<Map.Entry<String, Integer>> iterator = entries.iterator(); while(iterator.hasNext()){ Map.Entry<String, Integer> next = iterator.next(); String key = next.getKey(); Integer value = next.getValue(); System.out.println("[ "+key+" ]年: 发行( "+value+" )部电影"); } }