JSON.DEFFAULT_DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";

        TestBean test = new TestBean();

        LocalDateTime time1 = LocalDateTime.now();
        LocalDateTime time2 = LocalDateTime.parse("2017-09-22 15:08:56", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        test.setTime1(time1);
        test.setTime2(time2);

        String json = JSON.toJSONString(test, SerializerFeature.WriteDateUseDateFormat);
        System.out.println(json);