<pre>
/**

• 获取当前的年月天；

*/

• (NSInteger)currentYearMonthDay:(NSDate *)currentDate{
  NSCalendar calder = [NSCalendar currentCalendar];
  NSDateComponents complement = [calder components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay | NSCalendarUnitHour fromDate:currentDate];
  return complement.day;
  }
  /

• 获取每一个月的总天数
  */

• (NSInteger)totalDaysOfCurrentMounth:(NSDate *)currentDate{
  NSRange range = [[NSCalendar currentCalendar] rangeOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitMonth forDate:currentDate];
  return range.length;

}
/**

*/

• (NSString *)getMonthBeginAndEndWith:(NSDate *)date{

// NSDateFormatter *format=[[NSDateFormatter alloc] init];
// [format setDateFormat:@"yyyy-MM"];
// NSDate *newDate=[format dateFromString:dateStr];
double interval = 0;
NSDate *beginDate = nil;
NSDate *endDate = nil;
NSCalendar *calendar = [NSCalendar currentCalendar];

[calendar setFirstWeekday:2];//设定周日为周首
BOOL ok = [calendar rangeOfUnit:NSCalendarUnitMonth startDate:&beginDate interval:&interval forDate:date];
//分别修改为 NSDayCalendarUnit NSWeekCalendarUnit NSYearCalendarUnit
if (ok) {
    endDate = [beginDate dateByAddingTimeInterval:interval-1];
}else {
    return @"";
}
NSDateFormatter *myDateFormatter = [[NSDateFormatter alloc] init];
[myDateFormatter setDateFormat:@"YYYY.MM.dd"];
NSString *beginString = [myDateFormatter stringFromDate:beginDate];
NSString *endString = [myDateFormatter stringFromDate:endDate];
NSString *s = [NSString stringWithFormat:@"%@-%@",beginString,endString];
return s;

}
/**
*获取当前时间是星期几
*/

• (NSInteger)getWeekOfMonthWith:(NSDate )date{
  NSCalendar calendar = [NSCalendar currentCalendar];
  [calendar setFirstWeekday:2];
  return [calendar ordinalityOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitWeekOfMonth forDate:date];
  }
  /

• 时间字符串转化为date
  */

• (NSDate )getDateWithTimeString:(NSString )timeStr{
  NSDateFormatter inputFormatter = [[NSDateFormatter alloc] init];
  [inputFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:NSCalendarIdentifierGregorian] ];
  [inputFormatter setDateFormat:@"yyyyMMdd"];
  NSDate inputDate = [inputFormatter dateFromString:timeStr];
  return inputDate;
  }
  /
  每个月多少天
  */
  +(int)getDaysWithYear:(NSInteger )year andMonth:(NSInteger)month{
  int times [] = {31,28,31,30,31,30,31,31,30,31,30,31};
  if ((year%4==0&&year%100!=0)||year%400==0) {
  times[1] = 29;
  }
  return (times[month-1]);
  }
• (NSInteger)weeksOfMonthWithDate:(NSDate *)date{
  NSInteger firstDay = [self firstWeekdayInThisMonth:date];
  NSInteger totalDay = [self totalDaysOfCurrentMounth:date];
  NSInteger otherWeeks = (totalDay - (7-firstDay))/7;
  NSInteger otherDay = (totalDay - (7-firstDay))%7 == 0? 0:1 ;
  return 1+otherWeeks +otherDay;

}
/**

• 第一天是周几
  */

• (NSInteger)firstWeekdayInThisMonth:(NSDate *)date{
  NSCalendar *calendar = [NSCalendar currentCalendar];
  [calendar setFirstWeekday:1];//1.Sun. 2.Mon. 3.Thes. 4.Wed. 5.Thur. 6.Fri. 7.Sat.
  NSDateComponents *comp = [calendar components:(NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay) fromDate:date];
  [comp setDay:1];
  NSDate *firstDayOfMonthDate = [calendar dateFromComponents:comp];
  NSUInteger firstWeekday = [calendar ordinalityOfUnit:NSCalendarUnitWeekday inUnit:NSCalendarUnitWeekOfMonth forDate:firstDayOfMonthDate];
  return firstWeekday - 1;
  }
  //获取某某年某某月的第一天是星期几

+(int)GetTheWeekOfDayByYera:(int)year
andByMonth:(int)month{
int sum = 0;
for(int i = 1;i<month;i++){
sum+=[self getDaysWithYear:year andMonth:i];
}
int nedDay = sum+1;

return ((year-1)+(year-1)/4 -(year/100)+(year/400)+nedDay)%7;

}
/**

• 获取某一个月的第一天
  /
  +(NSDate)startDayOfCurrentMonth:(NSDate *)date{
  NSCalendar *calendar = [NSCalendar currentCalendar];
  NSDateComponents *startComplement = [calendar components:NSCalendarUnitYear|NSCalendarUnitMonth fromDate:date];
  [startComplement setHour:+8];

  NSDate *startDate = [calendar dateFromComponents:startComplement];
  return startDate;
  }

• (NSString *)autoFullString:(NSDate *)currentDate{
  NSCalendar *calder = [NSCalendar currentCalendar];
  NSDateComponents *complement = [calder components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay | NSCalendarUnitHour fromDate:currentDate];
  if (complement.month<10) {
  return [NSString stringWithFormat:@"%ld-0%ld",(long)complement.year,(long)complement.month];
  }
  return [NSString stringWithFormat:@"%ld-%ld",(long)complement.year,(long)complement.month];
  }

• (NSDate *)lastMonth:(NSDate *)date{
  NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
  dateComponents.month = -1;

  NSDate *newDate = [[NSCalendar currentCalendar] dateByAddingComponents:dateComponents toDate:date options:0];
  return newDate;
  }

• (NSDate*)nextMonth:(NSDate *)date{
  NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
  dateComponents.month = +1;
  NSDate *newDate = [[NSCalendar currentCalendar] dateByAddingComponents:dateComponents toDate:date options:0];
  return newDate;
  }
  </pre>

[转载一点其他]：http://www.111cn.net/sj/iOS/111617.htm

1、得到当前月第一天、最后一天日期

a、 本月开始日期
<pre>
func startOfCurrentMonth() -> NSDate {
let date = NSDate()
let calendar = NSCalendar.currentCalendar()
let components = calendar.components([.Year, .Month], fromDate: date)
let startOfMonth = calendar.dateFromComponents(components)!
return startOfMonth
}
</pre>
b、本月结束日期
<pre>
func endOfCurrentMonth(returnEndTime:Bool = false) -> NSDate {
let calendar = NSCalendar.currentCalendar()
let components = NSDateComponents()
components.month = 1
if returnEndTime {
components.second = -1
} else {
components.day = -1
}
let endOfMonth = calendar.dateByAddingComponents(components,
toDate: startOfCurrentMonth(),
options: [])!
return endOfMonth
}
</pre>
测试代码：

创建一个日期格式器
<pre>
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy年MM月dd日 HH:mm:ss"
</pre>

当月第一天日期
<pre>
let startDate = startOfCurrentMonth()
print("本月开始时间：", dateFormatter.stringFromDate(startDate))
</pre>

当月最后一天日期1<pre>
let endDate1 = endOfCurrentMonth()
print("本月结束时间1：", dateFormatter.stringFromDate(endDate1))
</pre>
当月最后一天日期2<pre>
let endDate2 = endOfCurrentMonth(true)
print("本月结束时间2：", dateFormatter.stringFromDate(endDate2))
</pre>

2、得到当年第一天、最后一天日期

a、本年开始日期
<pre>
func startOfCurrentYear() -> NSDate {
let date = NSDate()
let calendar = NSCalendar.currentCalendar()
let components = calendar.components([.Year], fromDate: date)
let startOfYear = calendar.dateFromComponents(components)!
return startOfYear
}
</pre>
b、本年结束日期
<pre>
func endOfCurrentYear(returnEndTime:Bool = false) -> NSDate {
let calendar = NSCalendar.currentCalendar()
let components = NSDateComponents()
components.year = 1
if returnEndTime {
components.second = -1
} else {
components.day = -1
}
let endOfYear = calendar.dateByAddingComponents(components,
toDate: startOfCurrentYear(),
options: [])!
return endOfYear
}
</pre>
测试代码：

创建一个日期格式器<pre>
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy年MM月dd日 HH:mm:ss"
</pre>
本年度第一天日期<pre>
let startDate = startOfCurrentYear()
print("本年度开始时间：", dateFormatter.stringFromDate(startDate))
</pre>
本年度最后一天日期1<pre>
let endDate1 = endOfCurrentYear()
print("本年度结束时间1：", dateFormatter.stringFromDate(endDate1))
</pre>
本年度最后一天日期2<pre>
let endDate2 = endOfCurrentYear(true)
print("本年度结束时间2：", dateFormatter.stringFromDate(endDate2))
</pre>

3、得到指定年月的第一天、最后一天日期

a、指定年月的开始日期<pre>
func startOfMonth(year: Int, month: Int) -> NSDate {
let calendar = NSCalendar.currentCalendar()
let startComps = NSDateComponents()
startComps.day = 1
startComps.month = month
startComps.year = year
let startDate = calendar.dateFromComponents(startComps)!
return startDate
}
</pre>
b、指定年月的结束日期 <pre>
func endOfMonth(year: Int, month: Int, returnEndTime:Bool = false) -> NSDate {
let calendar = NSCalendar.currentCalendar()
let components = NSDateComponents()
components.month = 1
if returnEndTime {
components.second = -1
} else {
components.day = -1
}
let endOfYear = calendar.dateByAddingComponents(components,
toDate: startOfMonth(year,
month:month), options: [])!
return endOfYear
} </pre>
测试代码：

创建一个日期格式器 <pre>
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy年MM月dd日 HH:mm:ss"
</pre>
当月第一天日期<pre>
let startDate = startOfMonth(2016, month: 8)
print("2016年8月的开始时间：", dateFormatter.stringFromDate(startDate))
</pre>
当月最后一天日期1<pre>
let endDate1 = endOfMonth(2016, month: 8)
print("2016年8月的结束时间1：", dateFormatter.stringFromDate(endDate1))
</pre>
当月最后一天日期2<pre>
let endDate2 = endOfMonth(2016, month: 8, returnEndTime: true)
print("2016年8月的结束时间2：", dateFormatter.stringFromDate(endDate2))
</pre>