/**
* 日期加减
*/
@Test
public void yesterdayCurrent() {
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
System.out.println(cal.getTime());
// Java 8
LocalDateTime today = LocalDateTime.now();
LocalDateTime yesterday = today.minusDays(1);
System.out.println(yesterday);
}
/**
* 获取年月日时分秒
*/
@Test
public void dateTimeTest() {
Calendar cal = Calendar.getInstance();
System.out.println(cal.get(Calendar.YEAR));
System.out.println(cal.get(Calendar.MONTH)); // 0 - 11
System.out.println(cal.get(Calendar.DATE));
System.out.println(cal.get(Calendar.HOUR_OF_DAY));
System.out.println(cal.get(Calendar.MINUTE));
System.out.println(cal.get(Calendar.SECOND));
System.out.println();
// Java 8
LocalDateTime dt = LocalDateTime.now();
System.out.println(dt.getYear());
System.out.println(dt.getMonthValue()); // 1 - 12
System.out.println(dt.getDayOfMonth());
System.out.println(dt.getHour());
System.out.println(dt.getMinute());
System.out.println(dt.getSecond());
}
/**
* 日期格式化
*/
@Test
public void dateFormatTest() {
SimpleDateFormat oldFormatter = new SimpleDateFormat("yyyy/MM/dd");
Date date1 = new Date();
System.out.println(oldFormatter.format(date1));
// Java 8
DateTimeFormatter newFormatter = DateTimeFormatter.ofPattern("yyyy/MM/dd");
LocalDate date2 = LocalDate.now();
System.out.println(date2.format(newFormatter));
}