在java中怎样根据第几周得到这一周的起始和结束日期，最好有代码

zhb01

在java中怎样根据第几周得到这一周的起始和结束日期，最好有代码         

wolfg

1. 
   
2. Calendar cal = new GregorianCalendar(2005, Calendar.JANUARY, 30);
   
3. 
   
4. int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
   
5. 
   
6. Calendar calFirstDayInThisWeek = (Calendar)cal.clone();
   
7. 
   
8. calFirstDayInThisWeek.add(Calendar.DATE, cal.getActualMinimum(Calendar.DAY_OF_WEEK)-dayOfWeek);
   
9. 
   
10. Calendar calLastDayInThisWeek = (Calendar)cal.clone();
    
11. 
    
12. calLastDayInThisWeek.add(Calendar.DATE,cal.getActualMaximum(Calendar.DAY_OF_WEEK)-dayOfWeek);
    

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白色乌鸦

呵呵，

类Calendar还是很强大的

zhb01

根据第ｘ年中第ｎ周取得这周起始和结束日期，以ｘ和ｎ为参数

wolfg

[quote]原帖由 "zhb01"]根据第ｘ年中第ｎ周取得这周起始和结束日期，以ｘ和ｎ为参数[/quote 发表：

道理差不多，可以从1月1号推算吧

1. 
   
2. Calendar calFirstDayOfTheYear = new GregorianCalendar(x,
   
3.                                     Calendar.JANUARY, 1);
   
4. calFirstDayOfTheYear.add(Calendar.DATE, 7 * (n-1));                   
   
5. 
   

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zhb01

按照楼上说必须指定１月１日为星期的第一天，然后推算每一天，我说的是按照正常日历来计算。

wolfg

[quote]原帖由 "zhb01"]按照楼上说必须指定１月１日为星期的第一天，然后推算每一天，我说的是按照正常日历来计算。[/quote 发表：


没有必须指定１月１日为星期的第一天，写程序要靠实践，Calendar 类的功能应该足够强大满足你的要求，你自己试试吧，我不过是丢块砖头罢了，也许有更好的解决办法

1. 
   
2. Calendar calFirstDayOfTheYear = new GregorianCalendar(year,
   
3.                                     Calendar.JANUARY, 1);
   
4.                     calFirstDayOfTheYear.add(Calendar.DATE, 7 * (week-1));
   
5.                    
   
6.                     dayOfWeek = calFirstDayOfTheYear.get(Calendar.DAY_OF_WEEK);
   
7.                     
   
8.                     Calendar calFirstDayInWeek = (Calendar)calFirstDayOfTheYear.clone();
   
9.                     calFirstDayInWeek.add(Calendar.DATE,
   
10.                                     calFirstDayOfTheYear.getActualMinimum(Calendar.DAY_OF_WEEK) - dayOfWeek);
    
11.                     Date firstDayInWeek = calFirstDayInWeek.getTime();
    
12.                     System.out.println(year + "年第" + week + "个礼拜的第一天是" + df.format(firstDayInWeek));
    
13.                     
    
14.                     Calendar calLastDayInWeek = (Calendar)calFirstDayOfTheYear.clone();
    
15.                     calLastDayInWeek.add(Calendar.DATE,
    
16.                                     calFirstDayOfTheYear.getActualMaximum(Calendar.DAY_OF_WEEK) - dayOfWeek);
    
17.                     Date lastDayInWeek = calLastDayInWeek.getTime();
    
18.                     System.out.println(year + "年第" + week + "个礼拜的第一天是" + df.format(lastDayInWeek));
    

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zhb01

int x=2007;
    int n=10;
    Calendar cal = new GregorianCalendar(x, Calendar.JANUARY, 1);
   
    int ff=cal.get(Calendar.DAY_OF_WEEK);
    int week=cal.get(Calendar.WEEK_OF_YEAR);
    System.out.println("week:"+week);
    System.out.println("ff:"+ff);
    switch(ff){
      case 1:
        cal.set(Calendar.DATE,7*(n-2)+ff+7);
        break;
      case 2:
        cal.set(Calendar.DATE,7*(n-2)+ff+6);
        break;
      case 3:
        cal.set(Calendar.DATE,7*(n-2)+ff+5);
        break;
      case 4:
        cal.set(Calendar.DATE,7*(n-2)+ff+4);
        break;
      case 5:
        cal.set(Calendar.DATE,7*(n-2)+ff+3);
        break;
      case 6:
        cal.set(Calendar.DATE,7*(n-2)+ff+2);
        break;
      case 7:
        cal.set(Calendar.DATE,7*(n-2)+ff+1);
        break;

    }
   
    System.out.println("cal 1:"+cal.getTime());
    int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
    System.out.println("dayOfWeek :"+dayOfWeek);
    Calendar calFirstDayInThisWeek = (Calendar) cal.clone();
    calFirstDayInThisWeek.add(Calendar.DATE, cal.getActualMinimum(Calendar.DAY_OF_WEEK)-dayOfWeek);
    Calendar calLastDayInThisWeek = (Calendar) cal.clone();
    calLastDayInThisWeek.add(Calendar.DATE,cal.getActualMaximum(Calendar.DAY_OF_WEEK)-dayOfWeek);
    Date startDate=calFirstDayInThisWeek.getTime();
    Date endDate=calLastDayInThisWeek.getTime();
        System.out.println("calFirstDayInThisWeek:"+calFirstDayInThisWeek.getTime());
    System.out.println("calLastDayInThisWeek:"+calLastDayInThisWeek.getTime());
    System.out.println("startDate:"+startDate.getTime());

wolfg

结果都一样

zhb01

先滚动到该年.

Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR,x);

滚动到周:

c.set(Calendar.WEEK_OF_YEAR,n);
得到该周第一天:
c.set(Calendar.DAY_OF_WEEK,1);
最后一天:

c.set(Calendar.DAY_OF_WEEK,7);