Question

java 获取当前日期是多少周

Answer 1

使用Calendar类
/**Calendar类中的.get(Calendar.DAY_OF_WEEK)可以获取当前日期是星期几
* 获取当前日期是星期几<br>
*
* @param dt
* @return 当前日期是星期几
*/
public static String getWeekOfDate(Date dt) {
String[] weekDays = {"星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"};
Calendar cal = Calendar.getInstance();
cal.setTime(dt);

int w = cal.get(Calendar.DAY_OF_WEEK) - 1;
if (w < 0)
w = 0;

return weekDays[w];
}

Answer 2

// jdk1.8 周日开一周第一天时
// ********格式化 每年的周数**************
int week = LocalDate.of(2019, 12, 30).get(WeekFields.ISO.weekOfWeekBasedYear());
int year = LocalDate.of(2019, 12, 30).get(WeekFields.ISO.weekBasedYear());
String formatWeek = new DecimalFormat("00").format(week);
System.out.println(year + "-" + formatWeek);// 2020-01
// ********格式化 每年的周数**************