使用Threadlocal来解决SimpleDateFormat的多线程安全问题

迷南。 2022-07-17 01:23 206阅读 0赞

[这个文章其实说的很清楚了][Link 1]

#### 下面是实际的代码部分 ####

public class JodaDateService implements DateService { 
    
        private Map<String, String> timeZoneMapping = ImmutableMap.of("LOH", "Europe/London", "HKH", "Asia/Hong_Kong", "NYH", "America/New_York");
        private Map<String, String> cutTimeMapping = ImmutableMap.of("LOH", "23:59", "HKH", "17:00", "NYH", "22:00");
    
        //使用ThreadLocal代替原来的new SimpleDateFormat
        private static final ThreadLocal<SimpleDateFormat> dateFormatter = new ThreadLocal<SimpleDateFormat>(){
            @Override
            protected SimpleDateFormat initialValue() {
                return  new SimpleDateFormat("yyyy-MM-dd");
            }
        };
    
        @Override
        public Date now() {
            return DateTime.now().toDate();
        }
    
        @Override
        public String today(String POGroup) {
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
            return dateFormatter.get().format(new DateTime().withZone(DateTimeZone.forID(this.timeZoneMapping.get(POGroup))).toLocalDateTime().toDate());
        }
    
        @Override
        public String getFinancialDate(String POGroup) {
            String rawCutOffTime = this.cutTimeMapping.get(POGroup);
            int cutoffHour = Integer.parseInt(rawCutOffTime.split(":")[0]);
            int cutoffMinute = Integer.parseInt(rawCutOffTime.split(":")[1]);
            int totalCutOffSeconds = cutoffHour * 3600 + cutoffMinute * 60;
            DateTime currentDateTime = new DateTime().withZone(DateTimeZone.forID(this.timeZoneMapping.get(POGroup)));
    
            int currentHour = currentDateTime.getHourOfDay();
            int currentMinute = currentDateTime.getMinuteOfHour();
            int totalCurrentSeconds = currentHour * 3600 + currentMinute * 60 + currentDateTime.getSecondOfMinute();
    
             //这里的new 不是线程安全的
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
            Date result;
            if (totalCurrentSeconds <= totalCutOffSeconds) {
                result = currentDateTime.toLocalDateTime().toDate();
            } else {
                result = currentDateTime.plusDays(1).toLocalDateTime().toDate();
            }
    // return dateFormat.format(result);
            return dateFormatter.get().format(result);
        }
    }

[Link 1]: http://www.cnblogs.com/peida/archive/2013/05/31/3070790.html%20%20%E2%80%9C%E8%BF%99%E4%B8%AA%E6%96%87%E7%AB%A0%E8%AF%B4%E7%9A%84%E5%BE%88%E5%A5%BD%E4%BA%86%E2%80%9D