Java 获取当前时间戳

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SimpleDateFormat是线程不安全的
推荐
1.使用ThreadLocal
2.apache commons-lang包的DateFormatUtils

public class Dateformat { 
   
    private static final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";
    private static ThreadLocal threadLocal = new ThreadLocal();
    public static void main(String[] args) throws ParseException { 
   
//        apache commons-lang包的DateFormatUtils或者FastDateFormat实现，apache保证是线程安全的，并且更高效
        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:SS");
        String format = dateFormat.format(new Date());
        System.out.println("1 常规 ============ "+format);

        Date date = getDate(new Date());
        System.out.println("2 Calendar ============ "+date);

        DateFormat dateFormat1 = getDateFormat();
        String format1 = dateFormat1.format(new Date());
        System.out.println("3 ThreadLocal ============ "+format1);

        String format2 = DateFormatUtils.format(new Date(), DATE_FORMAT);
        System.out.println("4 DateFormatUtils============ " + format2);
    }
    private static Date getDate(Date date) throws ParseException { 
   
        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:SS");
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.HOUR_OF_DAY, 1);
        return (Date) dateFormat.parseObject(dateFormat.format(calendar
                .getTime()));
    }

    public static DateFormat getDateFormat() { 
   
        DateFormat df = (DateFormat) threadLocal.get();
        if (df == null) { 
   
            df = new SimpleDateFormat(DATE_FORMAT);
            threadLocal.set(df);
        }
        return df;
    }
}

 String format = new SimpleDateFormat("yyyy-MM-dd").format(new Date());
 //sql.timestamp 
 Timestamp timestamp = new Timestamp(new Date().getTime());  
  //util.Date      
 String format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());

YYYYMMdd和yyyyMMdd的区别