java中怎么根据年月周算这周得日期

Question

java中怎么根据年月周算这周得日期
比如说 2006.05.09号是属于第19周得
第19周得日期起始为20060507-20060514号 怎么得到20060507呢？
请高手赐教，详细一点得。运行可以立马放分。

Answer 1

Calendar cal = Calendar.getInstance();
cal.set(2006,4,9);//2006-05-09
cal.set(Calendar.DAY_OF_WEEK,1);
System.out.println(cal.get(Calendar.YEAR)+"-"+(cal.get(Calendar.MONTH)+1)+"-"+cal.get(Calendar.DATE));
cal.set(Calendar.WEEK_OF_YEAR,cal.get(Calendar.WEEK_OF_YEAR)+1);
cal.set(Calendar.DAY_OF_WEEK,1);
System.out.println(cal.get(Calendar.YEAR)+"-"+(cal.get(Calendar.MONTH)+1)+"-"+cal.get(Calendar.DATE));

Answer 2

楼上的每周变8天拉，下面的才对
Calendar cal = Calendar.getInstance();
cal.set(2006,4,9);//2006-05-09
cal.set(Calendar.DAY_OF_WEEK,1);
System.out.println(cal.get(Calendar.YEAR)+"-"+(cal.get(Calendar.MONTH)+1)+"-"+cal.get(Calendar.DATE));
cal.set(Calendar.DAY_OF_WEEK,7);
System.out.println(cal.get(Calendar.YEAR)+"-"+(cal.get(Calendar.MONTH)+1)+"-"+cal.get(Calendar.DATE));

Answer 3

//每周的第一天从周日算器
Calendar cal = Calendar.getInstance();
cal.set(2006,4,9);//2006-05-09
cal.set(Calendar.DAY_OF_WEEK,1);
System.out.println("第一天:" + cal.get(Calendar.YEAR)+"-"+(cal.get(Calendar.MONTH)+1)+"-"+cal.get(Calendar.DATE));
cal.set(Calendar.DAY_OF_WEEK,7);
System.out.println("第七天:" + cal.get(Calendar.YEAR)+"-"+(cal.get(Calendar.MONTH)+1)+"-"+cal.get(Calendar.DATE));
将上述代码放置在main方法中间,运行即可得到你要求的

Answer 4

给你几个很好用的方法：
public class ManageWeek {
 //判断两个日期是否在同一周
 boolean isSameWeekDates(Date date1, Date date2) {
  Calendar cal1 = Calendar.getInstance();
  Calendar cal2 = Calendar.getInstance();
  cal1.setTime(date1);
  cal2.setTime(date2);
  int subYear = cal1.get(Calendar.YEAR) - cal2.get(Calendar.YEAR);
  if (0 == subYear) {
    if (cal1.get(Calendar.WEEK_OF_YEAR) == cal2.get(Calendar.WEEK_OF_YEAR))
   return true;
  }
  else if (1 == subYear && 11 == cal2.get(Calendar.MONTH)) {
    // 如果12月的最后一周横跨来年第一周的话则最后一周即算做来年的第一周
    if (cal1.get(Calendar.WEEK_OF_YEAR) == cal2.get(Calendar.WEEK_OF_YEAR))
   return true;
  }
  else if (-1 == subYear && 11 == cal1.get(Calendar.MONTH)) {
    if (cal1.get(Calendar.WEEK_OF_YEAR) == cal2.get(Calendar.WEEK_OF_YEAR))
   return true;
  }
  return false;
 }
 
 
 //产生周序列
 public static String  getSeqWeek(){
  Calendar c = Calendar.getInstance(Locale.CHINA);
  String week = Integer.toString(c.get(Calendar.WEEK_OF_YEAR));
  if(week.length()==1)week = "0" + week;
  String year = Integer.toString(c.get(Calendar.YEAR));  
  return year+week;
  
 }
  
  //获得周一的日期
  public static String getMonday(Date date){
   Calendar c = Calendar.getInstance();
   c.setTime(date);
   c.set(Calendar.DAY_OF_WEEK,Calendar.MONDAY);
   return new SimpleDateFormat("yyyy-MM-dd").format(c.getTime());
  }
  
  
  //获得周五的日期
  public static String getFriday(Date date){
   Calendar c = Calendar.getInstance();
   c.setTime(date);
   c.set(Calendar.DAY_OF_WEEK,Calendar.FRIDAY);   
   return new SimpleDateFormat("yyyy-MM-dd").format(c.getTime());  
  }//当前日期前几天或者后几天的日期 public static String afterNDay(int n){
        Calendar c=Calendar.getInstance();
        DateFormat df=new SimpleDateFormat("yyyy-MM-dd");
        c.setTime(new Date());
        c.add(Calendar.DATE,n);
        Date d2=c.getTime();
        String s=df.format(d2);
        return s;
    }

Answer 5

这几个方法就是你要的：  //产生周序列 //获得周一的日期 //获得周五的日期 //产生周序列
 public static String  getSeqWeek(){
  Calendar c = Calendar.getInstance(Locale.CHINA);
  String week = Integer.toString(c.get(Calendar.WEEK_OF_YEAR));
  if(week.length()==1)week = "0" + week;
  String year = Integer.toString(c.get(Calendar.YEAR));  
  return year+week;
  
 }
  
  //获得周一的日期
  public static String getMonday(Date date){
   Calendar c = Calendar.getInstance();
   c.setTime(date);
   c.set(Calendar.DAY_OF_WEEK,Calendar.MONDAY);
   return new SimpleDateFormat("yyyy-MM-dd").format(c.getTime());
  }
  
  
  //获得周五的日期
  public static String getFriday(Date date){
   Calendar c = Calendar.getInstance();
   c.setTime(date);
   c.set(Calendar.DAY_OF_WEEK,Calendar.FRIDAY);   
   return new SimpleDateFormat("yyyy-MM-dd").format(c.getTime());  
  }