获取一年有多少周、某周的第一天和最后一天代码,Java代码库,德仔网

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【Java】获取一年有多少周、某周的第一天和最后一天
作者:追风筝的人 / 发布于2015/7/9/ 731

	import java.text.SimpleDateFormat;
	import java.util.Calendar;
	import java.util.Date;
	import java.util.GregorianCalendar;
	
	
	public class Test {
	
	 // 获取当前时间所在年的周数
	 public static int getWeekOfYear(Date date) {
	 Calendar c = new GregorianCalendar();
	 c.setFirstDayOfWeek(Calendar.MONDAY);
	 c.setMinimalDaysInFirstWeek(7);
	 c.setTime(date);
	
	 return c.get(Calendar.WEEK_OF_YEAR);
	 }
	
	 // 获取当前时间所在年的最大周数
	 public static int getMaxWeekNumOfYear(int year) {
	 Calendar c = new GregorianCalendar();
	 c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);
	
	 return getWeekOfYear(c.getTime());
	 }
	
	 // 获取某年的第几周的开始日期
	 public static Date getFirstDayOfWeek(int year, int week) {
	 Calendar c = new GregorianCalendar();
	 c.set(Calendar.YEAR, year);
	 c.set(Calendar.MONTH, Calendar.JANUARY);
	 c.set(Calendar.DATE, 1);
	
	 Calendar cal = (GregorianCalendar) c.clone();
	 cal.add(Calendar.DATE, week * 7);
	
	 return getFirstDayOfWeek(cal.getTime());
	 }
	
	 // 获取某年的第几周的结束日期
	 public static Date getLastDayOfWeek(int year, int week) {
	 Calendar c = new GregorianCalendar();
	 c.set(Calendar.YEAR, year);
	 c.set(Calendar.MONTH, Calendar.JANUARY);
	 c.set(Calendar.DATE, 1);
	
	 Calendar cal = (GregorianCalendar) c.clone();
	 cal.add(Calendar.DATE, week * 7);
	
	 return getLastDayOfWeek(cal.getTime());
	 }
	
	 // 获取当前时间所在周的开始日期
	 public static Date getFirstDayOfWeek(Date date) {
	 Calendar c = new GregorianCalendar();
	 c.setFirstDayOfWeek(Calendar.MONDAY);
	 c.setTime(date);
	 c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); // Monday
	 return c.getTime();
	 }
	
	 // 获取当前时间所在周的结束日期
	 public static Date getLastDayOfWeek(Date date) {
	 Calendar c = new GregorianCalendar();
	 c.setFirstDayOfWeek(Calendar.MONDAY);
	 c.setTime(date);
	 c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6); // Sunday
	 return c.getTime();
	 }
	
	 public static void main(String[] args) {
	 int year = 2015;
	 int week = 27;
	
	 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
	 Date today = new Date();
	 Calendar c = new GregorianCalendar();
	 c.setTime(today);
	
	 System.out.println("当前时间:current date = " + sdf.format(today));
	 System.out.println("当前第几周:getWeekOfYear = " + getWeekOfYear(today));
	 System.out.println("年度总周数:getMaxWeekNumOfYear = " + getMaxWeekNumOfYear(year));
	 System.out.println("本周第一天:getFirstDayOfWeek = " + sdf.format(getFirstDayOfWeek(year, week)));
	 System.out.println("本周最后一天:getLastDayOfWeek = " + sdf.format(getLastDayOfWeek(year, week)));
	 System.out.println("本周第一天:getFirstDayOfWeek = " + sdf.format(getFirstDayOfWeek(today)));
	 System.out.println("本周最后一天:getLastDayOfWeek = " + sdf.format(getLastDayOfWeek(today)));
	 }
	}
	
	
	
	 //输出结果:
	// 当前时间:current date = 2015-07-07 16:35:07
	// 当前第几周:getWeekOfYear = 27
	// 年度总周数:getMaxWeekNumOfYear = 52
	// getFirstDayOfWeek = 2015-07-06 16:35:07
	// getLastDayOfWeek = 2015-07-12 16:35:07
	// getFirstDayOfWeek = 2015-07-06 16:35:07
	// getLastDayOfWeek = 2015-07-12 16:35:07
试试其它关键字
　最后一天　　第一天　
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