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mahaijiang 发表于 2015-07-08 10:41

Java获取一年有多少周、某周的第一天和最后一天

Java获取一年有多少周、某周的第一天和最后一天.

原文地址:http://blog.csdn.net/dragonvsdragon/article/details/7034007import 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

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