iOS 时间戳和时间互换,计算两日期相隔天数

/*
 *获取当前系统时间的时间戳
 */
+(NSInteger)getNowTimestamp;
 
/**
 * 获取当前时间
 */
+ (NSString *)getNowTimeTampFormat:(NSString *)tampFormat;
/*
 *时间戳转时间
 *format (@"YYYY-MM-dd hh:mm:ss") ----------设置你想要的格式,hh与HH的区别:分别表示12小时制,24小时制
 */
+(NSString *)timestampSwitchTime:(NSInteger)timestamp andFormatter:(NSString *)format;
    
/*
 *时间戳转时间(时间的前一天)
 *format (@"YYYY-MM-dd hh:mm:ss") ----------设置你想要的格式,hh与HH的区别:分别表示12小时制,24小时制
 */
+(NSString *)timestampSwitchlastTime:(NSInteger)timestamp andFormatter:(NSString *)format;
 
 
/*
 *时间戳转时间
 *formatTime 时间字符串
 *format (@"YYYY-MM-dd hh:mm:ss") ----------设置你想要的格式,hh与HH的区别:分别表示12小时制,24小时制
 */
+ (NSInteger)timeSwitchTimestamp:(NSString *)formatTime andFormatter:(NSString *)format;
/*
 *某日和当前日期相隔多少天
 */
+ (NSInteger)getDifferenceByDate:(NSString *)date;
 
/**
 *日期格式请传入：2013-08-05 12:12:12；如果修改日期格式，比如：2013-08-05，则将[df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];修改为[df setDateFormat:@"yyyy-MM-dd"];
 */
+(int)compareDate:(NSString*)date01 withDate:(NSString*)date02;

+(NSInteger)getNowTimestamp{
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    
    [formatter setDateStyle:NSDateFormatterMediumStyle];
    
    [formatter setTimeStyle:NSDateFormatterShortStyle];
    
    [formatter setDateFormat:@"YYYY-MM-dd HH:mm:ss"]; // ----------设置你想要的格式,hh与HH的区别:分别表示12小时制,24小时制
    
    //设置时区,这个对于时间的处理有时很重要
    
    NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:@"Asia/Beijing"];
    
    [formatter setTimeZone:timeZone];
    
    NSDate *datenow = [NSDate date];//现在时间
    
//    NSLog(@"设备当前的时间:%@",[formatter stringFromDate:datenow]);
    
    //时间转时间戳的方法:
    
    NSInteger timeSp = [[NSNumber numberWithDouble:[datenow timeIntervalSince1970]] integerValue];
    
//    NSLog(@"设备当前的时间戳:%ld",(long)timeSp); //时间戳的值
    
    return timeSp;
    
}
+ (NSString *)getNowTimeTampFormat:(NSString *)tampFormat {
 
    NSDate *date = [NSDate date];
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    
    [formatter setDateStyle:NSDateFormatterMediumStyle];
    
    [formatter setTimeStyle:NSDateFormatterShortStyle];
    
    [formatter setDateFormat:tampFormat];
    NSString *DateTime = [formatter stringFromDate:date];
    
    return DateTime;
}
 
//将某个时间戳转化成 时间
 
#pragma mark - 将某个时间戳转化成 时间
 
+(NSString *)timestampSwitchTime:(NSInteger)timestamp andFormatter:(NSString *)format {
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    
    [formatter setDateStyle:NSDateFormatterMediumStyle];
    
    [formatter setTimeStyle:NSDateFormatterShortStyle];
    
    [formatter setDateFormat:format];
    NSTimeZone *timeZone = [NSTimeZone timeZoneWithName:@"Asia/Beijing"];
    
    [formatter setTimeZone:timeZone];
    //十三位时间戳转时间需要/1000 十位时间戳你不需要
    NSDate *confromTimesp = [NSDate dateWithTimeIntervalSince1970:timestamp / 1000];
    
    
    NSString *confromTimespStr = [formatter stringFromDate:confromTimesp];
    
//    NSLog(@"&&&&&&&confromTimespStr = : %@",confromTimespStr);
    
    return confromTimespStr;
    
}
 
/*
 *时间戳转时间(时间的前一天)
 *format (@"YYYY-MM-dd hh:mm:ss") ----------设置你想要的格式,hh与HH的区别:分别表示12小时制,24小时制
 */
+(NSString *)timestampSwitchlastTime:(NSInteger)timestamp andFormatter:(NSString *)format {
 
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    
    [formatter setDateStyle:NSDateFormatterMediumStyle];
    
    [formatter setTimeStyle:NSDateFormatterShortStyle];
    
    [formatter setDateFormat:format];
    NSTimeZone *timeZone = [NSTimeZone timeZoneWithName:@"Asia/Beijing"];
    
    [formatter setTimeZone:timeZone];
    //十三位时间戳转时间需要/1000 十位时间戳你不需要
    NSDate *confromTimesp = [NSDate dateWithTimeIntervalSince1970:timestamp / 1000];
    
    NSDate *lastDay = [NSDate dateWithTimeInterval:(-24*60*60)*2 sinceDate:confromTimesp];//前两天
    
    NSString *confromTimespStr = [formatter stringFromDate:lastDay];
 
    return confromTimespStr;
 
}
 
//将某个时间转化成 时间戳
 
#pragma mark - 将某个时间转化成 时间戳
 
+ (NSInteger)timeSwitchTimestamp:(NSString *)formatTime andFormatter:(NSString *)format{
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    
    [formatter setDateStyle:NSDateFormatterMediumStyle];
    
    [formatter setTimeStyle:NSDateFormatterShortStyle];
    
    [formatter setDateFormat:format];     
    NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:@"Asia/Beijing"];
    
    [formatter setTimeZone:timeZone];
    
    
    NSDate* date = [formatter dateFromString:formatTime]; //------------将字符串按formatter转成nsdate
    
    //时间转时间戳的方法:
    
    NSInteger timeSp = [[NSNumber numberWithDouble:[date timeIntervalSince1970]] integerValue];
    
//    NSLog(@"将某个时间转化成 时间戳&&&&&&&timeSp:%ld",(long)timeSp); //时间戳的值
    
    return timeSp;
}
 
+ (NSInteger)getDifferenceByDate:(NSString *)date {
    //获得当前时间
//    NSDate *now = [NSDate date];
//    //实例化一个NSDateFormatter对象
//    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
//    //设定时间格式
//    [dateFormatter setDateFormat:@"YYYY-MM-dd"];
//    NSDate *oldDate = [dateFormatter dateFromString:date];
//    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
//    unsigned int unitFlags = NSDayCalendarUnit;
//    NSDateComponents *comps = [gregorian components:unitFlags fromDate:oldDate  toDate:now  options:0];
//    return [comps day];
//
    //下面这种方法从00:00:00开始计算
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    NSCalendar *gregorian = [[NSCalendar alloc]
                             initWithCalendarIdentifier:NSGregorianCalendar];
    [gregorian setFirstWeekday:2];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"YYYY-MM-dd"];
    NSDate *fromDate;
    NSDate *toDate;
    [gregorian rangeOfUnit:NSDayCalendarUnit startDate:&fromDate interval:NULL forDate:[dateFormatter dateFromString:date]];
    [gregorian rangeOfUnit:NSDayCalendarUnit startDate:&toDate interval:NULL forDate:[NSDate date]];
    NSDateComponents *dayComponents = [gregorian components:NSDayCalendarUnit fromDate:fromDate toDate:toDate options:0];
#pragma clang diagnostic pop
 
    return [dayComponents day];
}
 
 
+(int)compareDate:(NSString*)date01 withDate:(NSString*)date02 {
    int ci;
    NSDateFormatter *df = [[NSDateFormatter alloc] init];
    [df setDateFormat:@"yyyy-MM-dd"];
    NSDate *dt1 = [[NSDate alloc] init];
    NSDate *dt2 = [[NSDate alloc] init];
    dt1 = [df dateFromString:date01];
    dt2 = [df dateFromString:date02];
    NSComparisonResult result = [dt1 compare:dt2];
    switch (result) {
            //date02比date01大
        case NSOrderedAscending: ci=1; break;
            //date02比date01小
        case NSOrderedDescending: ci=-1; break;
            //date02=date01
        case NSOrderedSame: ci=0; break;
        default: NSLog(@"erorr dates %@, %@", dt2, dt1); break;
    }
    return ci;
}