java 判断map是否存在某个key 和 json字符串转化为list对象

    
                equipment = new ECEquipment();
                
                if(map.containsKey(cell5))
                {
                    map.get(cell5).add(equipment);
                }
                else
                {
                    equipmentList = new ArrayList<ECEquipment>();
                    equipmentList.add(equipment);
                    
                    map.put(cell5, equipmentList);
                }
                

String jsonString = "[{\"fileId\":\"o_1b1esbhjf1f2ki7310dfmjc9728\",\"fileName\":\"2.jpg\"}]";
        
          JSONArray json = JSONArray.fromObject(jsonString);
          List<AliyunFileModel> list = (List<AliyunFileModel>)JSONArray.toCollection(json, AliyunFileModel.class);
          
          System.out.println(list);