Question

我有周数和年份，我想得到一周的第一天和最后一天的日期，这是我的代码，它给了我错误的结果，请告诉我我是什么？做错了。提前谢谢。

SimpleDateFormat dt = new SimpleDateFormat("dd/mm/yyyy"); 
String start ="";
String end ="";
int week = 38;
int yeat = 2016;
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.WEEK_OF_YEAR, week);
calendar.set(Calendar.YEAR, year); 
// firt day of week
start = dt.format(calendar.getTime());
calendar.add(Calendar.DAY_OF_MONTH, 6);
//last day of week
end = dt.format(calendar.getTime());

Answer 1

如果您使用Java 8+，则可以使用内置的周日期格式化程序：

int week = 38;
int year = 2016;
String weekYear = year + "-W" + week + "-7"; //2016-W38-7
LocalDate d = LocalDate.parse(year + "-W" + week + "-7", ISO_WEEK_DATE); //2016-09-25

注意：字符串末尾的-7代表一周的最后一天（即星期日）。

Answer 2

更正DateFormatter语法，月份应为大写字母

获取该特定周的周日和周六的日期一年过去了。

  SimpleDateFormat dt = new SimpleDateFormat("dd/MM/yyyy"); 
     String start ="";
     String end ="";
     int week = 38;
     int year = 2016;
     Calendar calendar = Calendar.getInstance();
     calendar.set(Calendar.YEAR, year); 
     calendar.set(Calendar.DAY_OF_WEEK,Calendar.SUNDAY);
     calendar.set(Calendar.WEEK_OF_YEAR, week);
      start = dt.format(calendar.getTime());
     calendar.set(Calendar.DAY_OF_WEEK,Calendar.SATURDAY);
       end = dt.format(calendar.getTime());
     System.out.println(start+" |"+end);

Answer 3

试试这个：

SimpleDateFormat dt = new SimpleDateFormat("dd/mm/yyyy"); 
String start ="";
String end ="";
int week = 38;
int year = 2016;
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.WEEK_OF_YEAR, week);
calendar.set(Calendar.YEAR, year); 

// firt day of week
Calendar cal = calendar;
while (cal.get(Calendar.DAY_OF_WEEK) != Calendar.SUNDAY) {
    cal.add(Calendar.DATE, -1);
}
start = dt.format(cal.getTime());
System.out.println(start);

Calendar cal1 = calendar;
while (cal1.get(Calendar.DAY_OF_WEEK) != Calendar.SATURDAY) {
    cal1.add(Calendar.DATE, 1);
}
//last day of week
end = dt.format(cal1.getTime());
System.out.println(end);

给周数和年份找到第一天和一周的最后一天

3 个答案: