java 本月的第一天和最后一天 一个月的第一天和最后一天

 

/**  
 * 得到本月的第一天  
 * @return  
 */  
public static String getMonthFirstDay() {   
    Calendar calendar = Calendar.getInstance();   
    calendar.set(Calendar.DAY_OF_MONTH, calendar   
            .getActualMinimum(Calendar.DAY_OF_MONTH));   
  
    return dateFormat("yyyy-MM-dd", calendar.getTime());   
}   
  
/**  
 * 得到本月的最后一天  
 *   
 * @return  
 */  
public static String getMonthLastDay() {   
    Calendar calendar = Calendar.getInstance();   
    calendar.set(Calendar.DAY_OF_MONTH, calendar   
            .getActualMaximum(Calendar.DAY_OF_MONTH));   
    return dateFormat("yyyy-MM-dd", calendar.getTime());   
}   

 

 

 

/**
	 * 
	 * @param year
	 *            int 年份
	 * @param month
	 *            int 月份
	 * 
	 * @return int 某年某月的最后一天
	 */
	private int getLastDayOfMonth(int year, int month) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, month);
		// 某年某月的最后一天
		return cal.getActualMaximum(Calendar.DATE);
	}

 需要注意的是：月份是从0开始的，比如说如果输入5的话，实际上显示的是4月份的最后一天，千万不要搞错了哦

评论

2 楼 cooltain 2011-11-08  

可以收藏吧

1 楼 yiwenqi2011 2011-08-15  

private static Map<String, String> findLastMonth() {
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");

Calendar cal = Calendar.getInstance();
GregorianCalendar gcLast = (GregorianCalendar) Calendar.getInstance();
Calendar calendar = Calendar.getInstance();
calendar.setTime(new Date());

calendar.add(Calendar.MONTH, -1);
Date theDate = calendar.getTime();
gcLast.setTime(theDate);
gcLast.set(Calendar.DAY_OF_MONTH, 1);
String day_first_prevM = df.format(gcLast.getTime());
StringBuffer str = new StringBuffer().append(day_first_prevM).append(
" 00:00:00");
day_first_prevM = str.toString();

calendar.add(cal.MONTH, 1);
calendar.set(cal.DATE, 1);
calendar.add(cal.DATE, -1);
String day_end_prevM = df.format(calendar.getTime());
StringBuffer endStr = new StringBuffer().append(day_end_prevM).append(
" 23:59:59");
day_end_prevM = endStr.toString();

Map<String, String> map = new HashMap<String, String>();
map.put("prevMonthFD", day_first_prevM);
map.put("prevMonthPD", day_end_prevM);
return map;
}



public static String getLastDay(){

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
Calendar calendar = Calendar.getInstance();//此时打印它获取的是系统当前时间
calendar.add(Calendar.DATE, -1); //
Date theDate = calendar.getTime();
String s = df.format(theDate);
System.out.println(s);

return s;

}