+(NSString*)ChatingTime:(NSString *)timestring{

    int timestamp=  [timestring intValue];

        // 创建日历对象

        NSCalendar *calendar = [NSCalendar currentCalendar];

        // 获取当前时间

    NSDate *currentDate = [NSDate date];

        // 获取当前时间的年、月、日。利用日历

        NSDateComponents *components = [calendar components:NSCalendarUnitYear| NSCalendarUnitMonth|NSCalendarUnitDay fromDate:currentDate];

        NSInteger currentYear = components.year;

        NSInteger currentMonth = components.month;

        NSInteger currentDay = components.day;

        // 获取消息发送时间的年、月、日

        NSDate *msgDate = [NSDate dateWithTimeIntervalSince1970:timestamp];

        components = [calendar components:NSCalendarUnitYear| NSCalendarUnitMonth|NSCalendarUnitDay|NSCalendarUnitHour fromDate:msgDate];

        CGFloat msgYear = components.year;

        CGFloat msgMonth = components.month;

        CGFloat msgDay = components.day;

        CGFloat msghours = components.hour;

        // 进行判断

        NSDateFormatter *dateFmt = [[NSDateFormatter alloc] init];

        if (currentYear == msgYear && currentMonth == msgMonth && currentDay == msgDay) {

            //今天

            if (msghours<) {

                dateFmt.dateFormat = @"上午 hh:mm";

            }else{

                dateFmt.dateFormat = @"下午 hh:mm";

            }

        }else if (currentYear == msgYear && currentMonth == msgMonth && currentDay- == msgDay ){

            //昨天

            dateFmt.dateFormat = @"昨天 HH:mm";

        }else{

            //昨天以前

            dateFmt.dateFormat = @"MM-dd HH:mm";

        }

        // 返回处理后的结果

        return [dateFmt stringFromDate:msgDate];

}