时间：小时差、TZ的时间处理

一、Timestamp类型的小时差计算

@Test
    public void test111() throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date d = sdf.parse("2020-09-23 00:50:00");
        long time1 = d.getTime();
        long time = sdf.parse("2020-09-23 10:00:00").getTime();
        long l = time - time1;
        double a =(double)l /(60*60*1000);
        DecimalFormat df = new DecimalFormat("0.0");
        String format = df.format(a);
        System.out.println("time: "+time);
        System.out.println("time1: "+time1);
        System.out.println("l: "+l);
        System.out.println("l1: "+a);
        System.out.println("format: "+format);
    }

	// 输出：
	// time: 1600826400000
	// time1: 1600793400000
	// l: 33000000
	// l1: 9.166666666666666
	// format: 9.2

二、TZ的时间处理：转换成Timestamp类型

@Test
    public void test121() throws ParseException {
        String s= "2021-04-23T16:00:00.000Z";
        String s1 = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
        Date date = null;
        SimpleDateFormat sdf = new SimpleDateFormat(s1);
        date = sdf.parse(s);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.HOUR, calendar.get(Calendar.HOUR) + 8);
        Date time = calendar.getTime();
        System.out.println("UTC时间: " + date);
        System.out.println("北京时间: " + calendar.getTime()); //calendar.getTime() 返回的是Date类型，也可以使用calendar.getTimeInMillis()获取时间戳
        System.out.println("Date时间：" + time);
        System.out.println("Timestamp类型：" + new Timestamp(time.getTime()));
    }
    输出：
    // UTC时间: Fri Apr 23 16:00:00 CST 2021
	// 北京时间: Sat Apr 24 00:00:00 CST 2021
	// Date时间：Sat Apr 24 00:00:00 CST 2021
	// Timestamp类型：2021-04-24 00:00:00.0