JAVA 根據具體年份周數獲取日期范圍

/**
* 根據具體年份周數獲取日期范圍
* @param year
* @param week
* @param targetNum
* @return
*/
public String getWeekDays(int year, int week, int targetNum) {
　

　　// 計算目標周數
　　if (week + targetNum > 52) {
　　　　year++;
　　　　week += targetNum - 52;
　　} else if (week + targetNum <= 0) {
　　　　year--;
　　　　week += targetNum + 52;
　　} else {
　　　　week += targetNum;
　　}

　　SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
　　Calendar cal=Calendar.getInstance();

　　// 設置每周的開始日期
　　cal.setFirstDayOfWeek(Calendar.SUNDAY);

　　cal.set(Calendar.YEAR, year);
　　cal.set(Calendar.WEEK_OF_YEAR, week);

　　cal.set(Calendar.DAY_OF_WEEK, cal.getFirstDayOfWeek());
　　String beginDate = sdf.format(cal.getTime());

　　cal.add(Calendar.DAY_OF_WEEK, 6);
　　String endDate = sdf.format(cal.getTime());

　　return beginDate + "~" + endDate;
}