一、例如：

? ? ? ? ? ? ? ?NSString *ceShiStr = [self getWeekDay:@"2016-12-04"];

? ? ? ? ? ? ? ?NSLog(@"ceShiStr = %@",ceShiStr);

? ? ? ? ? ? ? ?打印結果 : 周日

- (NSString*)getWeekDay:(NSString*)currentStr

{

NSDateFormatter* dateFormat = [[NSDateFormatteralloc]init];//實例化一個NSDateFormatter對象

[dateFormatsetDateFormat:@"yyyy-MM-dd"];//設定時間格式,要注意跟下面的dateString匹配，否則日起將無效

NSDate*date =[dateFormatdateFromString:currentStr];

NSArray*weekdays = [NSArrayarrayWithObjects: [NSNullnull],@"周日",@"周一",@"周二",@"周三",@"周四",@"周五",@"周六",nil];

NSCalendar*calendar = [[NSCalendaralloc]initWithCalendarIdentifier:NSCalendarIdentifierGregorian];

NSTimeZone*timeZone = [[NSTimeZonealloc]initWithName:@"Asia/Shanghai"];

[calendarsetTimeZone: timeZone];

NSCalendarUnitcalendarUnit =NSCalendarUnitWeekday;

NSDateComponents*theComponents = [calendarcomponents:calendarUnitfromDate:date];

return[weekdaysobjectAtIndex:theComponents.weekday];

}