ExpIssue exp = new ExpIssue();
    exp.setCreateTime(new Date());
    exp.setDealContent("liahodbfoasdhf");
第一种： String jstr = JSON.toJSONStringWithDateFormat(exp, "yyyy-MM-dd HH:mm:ss");
第二种： String ste =  JSON.toJSONString(exp, SerializerFeature.WriteDateUseDateFormat);
第三种：SerializeConfig mapping = new SerializeConfig();
       mapping.put(Date.class, new SimpleDateFormatSerializer("yyyy-MM-dd HH:mm:ss"));
       String json = JSONObject.toJSONString(issue,mapping,SerializerFeature.WriteDateUseDateFormat);
            
            

Please ask the experts for help, which one has better performance on the basis of accurate conversion under high concurrency