Java获得某月第一天和最后一天(Calendar实现)

 

1. import java.text.SimpleDateFormat;

2. import java.util.Calendar;

3. /**

4. * 获得该月第一天

5. * @param year

6. * @param month

7. * @return

8. */

9. public static String getFirstDayOfMonth(int year,int month){

10. Calendar cal = Calendar.getInstance();

11. //设置年份

12. cal.set(Calendar.YEAR,year);

13. //设置月份

14. cal.set(Calendar.MONTH, month-1);

15. //获取某月最小天数

16. int firstDay = cal.getActualMinimum(Calendar.DAY_OF_MONTH);

17. //设置日历中月份的最小天数

18. cal.set(Calendar.DAY_OF_MONTH, firstDay);

19. //格式化日期

20. SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

21. String firstDayOfMonth = sdf.format(cal.getTime());

22. return firstDayOfMonth;

23. }

24.  

25. /**

26. * 获得该月最后一天

27. * @param year

28. * @param month

29. * @return

30. */

31. public static String getLastDayOfMonth(int year,int month){

32. Calendar cal = Calendar.getInstance();

33. //设置年份

34. cal.set(Calendar.YEAR,year);

35. //设置月份

36. cal.set(Calendar.MONTH, month-1);

37. //获取某月最大天数

38. int lastDay = cal.getActualMaximum(Calendar.DAY_OF_MONTH);

39. //设置日历中月份的最大天数

40. cal.set(Calendar.DAY_OF_MONTH, lastDay);

41. //格式化日期

42. SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

43. String lastDayOfMonth = sdf.format(cal.getTime());

44. return lastDayOfMonth;

45. }