java取一年有多少周、某周的第一天喝醉后一天

快来打我* 2022-09-19 12:10 127阅读 0赞

import java.text.SimpleDateFormat;  
import java.util.Calendar;  
import java.util.Date;  
import java.util.GregorianCalendar;  
public class WeekUtils \{

// 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 = 2011;  
  int week = 1;

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
  Date today = new Date();  
  Calendar c = new GregorianCalendar();  
  c.setTime(today);

System.out.println("current date = " + sdf.format(today));  
  System.out.println("getWeekOfYear = " + getWeekOfYear(today));  
  System.out.println("getMaxWeekNumOfYear = " + getMaxWeekNumOfYear(year));  
  System.out.println("getFirstDayOfWeek = " + sdf.format(getFirstDayOfWeek(year, week)));  
  System.out.println("getLastDayOfWeek = " + sdf.format(getLastDayOfWeek(year, week)));  
  System.out.println("getFirstDayOfWeek = " + sdf.format(getFirstDayOfWeek(today)));  
  System.out.println("getLastDayOfWeek = " + sdf.format(getLastDayOfWeek(today)));  
 \}  
\}