问一个关于日期的算法，谢谢了，帮帮忙？？？？？？？？？

Question

有一个方法public void a(int i)i的值是1－7之间分别表示星期一到星期日，方法体实现的是求出当前是星期几我是这么实现的Calendar.getInstance().WEDNESDAY得到的是一个整型如今天是4,I的值是6通过这些条件，我应该怎么得到星期六的年月日时间。谢谢了大家了

Answer 1

public void a(int i){
       Calendar c = Calendar.getInstance();
       int day_of_week = c.get(Calendar.DAY_OF_WEEK);
       c.add(Calendar.DATE,i-day_of_week);
       int year = c.get(Calendar.YEAR);
       int month = c.get(Calendar.MONTH) + 1;
       int date = c.get(Calendar.DATE);
}

Answer 2

  /**
     * 获得一个日期所在的周的星期几的日期，如要找出2002年2月3日所在周的星期一是几号
     *
     * @param sdate
     * @param num
     * @return
     */
    public static String getWeek(String sdate, String num) {
        // 再转换为时间
        Date dd = DateFormats.strToDate(sdate);
        Calendar c = Calendar.getInstance();
        c.setTime(dd);
        if (num.equals("1")) // 返回星期一所在的日期
            c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
        else if (num.equals("2")) // 返回星期二所在的日期
            c.set(Calendar.DAY_OF_WEEK, Calendar.TUESDAY);
        else if (num.equals("3")) // 返回星期三所在的日期
            c.set(Calendar.DAY_OF_WEEK, Calendar.WEDNESDAY);
        else if (num.equals("4")) // 返回星期四所在的日期
            c.set(Calendar.DAY_OF_WEEK, Calendar.THURSDAY);
        else if (num.equals("5")) // 返回星期五所在的日期
            c.set(Calendar.DAY_OF_WEEK, Calendar.FRIDAY);
        else if (num.equals("6")) // 返回星期六所在的日期
            c.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);
        else if (num.equals("0")) // 返回星期日所在的日期
            c.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
        return new SimpleDateFormat("yyyy-MM-dd").format(c.getTime());
    }
http://javaprogram.5d6d.com/blog.php?tid=322

Answer 3

我怎么看不懂楼主在说什么呢？
你要得到星期六是几号？
            Calendar ca = Calendar.getInstance();
            ca.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);
            System.out.println(new SimpleDateFormat("yyyy-MM-dd").format(ca.getTime()));

Answer 4

public class Test {    public static void main(String[] args) {        
        Date date = getDate(Week.SUNDAY);
        System.out.printf("%tF%n", date);
    }
    
    private static Date getDate(Week week) {
        Calendar calendar = Calendar.getInstance();
        calendar.setFirstDayOfWeek(Week.MONDAY.getWeek());
        calendar.set(Calendar.DAY_OF_WEEK, week.getWeek());
        return calendar.getTime();
    }
}class Week {    
    private static int num = 1;    
    private int week = num++;
    
    private Week(){}
    
    public int getWeek() {
        return week;
    }
    
    public static Week SUNDAY = new Week();
    public static Week MONDAY = new Week();
    public static Week TUESDAY = new Week();
    public static Week WEDNESDAY = new Week();
    public static Week THURSDAY = new Week();
    public static Week FRIDAY = new Week();
    public static Week SATURDAY = new Week();
}

Answer 5

public void getWeekDay(int i)
  {
    Date date = new Date();
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    i = i+1;
    if(i >= 8)
    {
      i = i-7;
    }
    cal.set(Calendar.DAY_OF_WEEK, i);
  }

Answer 6

对一楼方法的改进public static void a(int i){
i+=1; //因为在JAVA中每周是从周日开始的,即周日是1,周一2
if(i>7)
i-=7;
Calendar c = Calendar.getInstance();
int day_of_week=c.get(Calendar.DAY_OF_WEEK);
c.add(Calendar.DAY_OF_WEEK,i-day_of_week);
int year=c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH)+1;
int day= c.get(Calendar.DAY_OF_MONTH);
System.out.println("year "+year+" month "+month+" day "+day);
}