FASTJSON 默认没有开启对泛型的支持。通过SerializerFeature.WriteClassName增加
Map<String, Date> map = new HashMap<String, Date>();
map.put("now", new Date());
String str = JSON.toJSONString(map,SerializerFeature.WriteClassName);
System.out.println(str);
Map<String, Date> result = JSON.parseObject(str, map.getClass());
System.out.println(result.get("now").getClass());