Javaで現在時刻を取得するいくつかの方法

SimpleDateFormat simpleFormat =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String datastring=si1.format(new Date());
//把获取的时间转换为date格式
Date insertDate=simpleFormat.parse(datastring);

long current=System.currentTimeMillis();//当前时间毫秒数

		Calendar rightNow = Calendar.getInstance(); // 子类对象
		// 获取年
		int year = rightNow.get(Calendar.YEAR);
		// 获取月
		int month = rightNow.get(Calendar.MONTH);
		// 获取日
		int date = rightNow.get(Calendar.DATE);
		// 获取几点
		int hour = rightNow.get(Calendar.HOUR_OF_DAY);
		// 获取上午下午
		int moa = rightNow.get(Calendar.AM_PM);
		if (moa == 1) {
			System.out.println("下午");
		} else {
			System.out.println("上午");
		}
		System.out.println(year + "年" + (month + 1) + "月" + date + "日" + hour + "时");
		rightNow.add(Calendar.YEAR, 5);
		rightNow.add(Calendar.DATE, -10);
		int year1 = rightNow.get(Calendar.YEAR);
		int date1 = rightNow.get(Calendar.DATE);
		System.out.println(year1 + "年" + (month + 1) + "月" + date1 + "日" + hour + "时");