Java 日历类 Calendar 相关方法

点击打开链接：http://www.open-open.com/lib/view/open1341648924464.html

/**
* 计算指定日期为当年第几周
* @param year		指定的年份
* @param month		指定的月份
* @param day		指定的日
* @return			指定日期为当年的第几周
*/
public static int caculateWeekOfYear(int year,int month,int day){
Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month - 1);
c.set(Calendar.DATE, day);
return c.get(Calendar.WEEK_OF_YEAR);
}

/**
* 获取本月第一天是星期几
* @return
*/
public static int getWeekOfFirstDay(Calendar c){
Calendar calendar = c;
calendar.set(Calendar.DAY_OF_MONTH, 1);
return calendar.get(Calendar.DAY_OF_WEEK);
}

/**
* 获取本月1号是该年的第几周
* @return
*/
public static int getMonthStartWeek(Calendar c){
Calendar calendar = c;
calendar.set(Calendar.DATE, 1);
return calendar.get(Calendar.WEEK_OF_YEAR);
}

/**
* 获取当天是该年的第几周
*/
public static int getCurrentWeekOfYear(){
Calendar calendar = Calendar.getInstance();
return calendar.get(Calendar.WEEK_OF_YEAR);
}

/**
* 获取上月的总天数
* @return
*/
public static int getLastMonthDays(Calendar c){
Calendar calendar = c;
calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH) - 1);
return calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
}

/**
* 获取指定月份的总天数
* @return
*/
public static int getCurrentMonthDays(int month){
Calendar c = Calendar.getInstance();
c.set(Calendar.MONTH, month);
return c.getActualMaximum(Calendar.DAY_OF_MONTH);
}

/**
* 获取指定年份有多少周
* @param year
* @return
*/
public static int getTotalWeekOfYear(int year){
Calendar c = Calendar.getInstance();
return c.getActualMaximum(Calendar.WEEK_OF_YEAR);
}

/**
* 判断指定月份是否是当前月
* @param month
* @return
*/
public static boolean isCurrentMonth(int month){
Calendar c = Calendar.getInstance();
return (c.get(Calendar.MONTH) == month)?true:false;
}

/**
* 计算指定的月份共有多少天
*/
public static int getTotalDaysOfMonth(int year, int month){
Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month);
c.set(Calendar.DATE, 1);
/**
* 计算这个月有多少天
*/
return c.getActualMaximum(Calendar.DAY_OF_MONTH);
}