时间和时间戳的相互转换

//获取当前时间

+ (NSString *)currentDateStr{
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateStyle:NSDateFormatterMediumStyle];
    [formatter setTimeStyle:NSDateFormatterShortStyle];
    [formatter setDateFormat:@"YYYY-MM-dd HH:mm:ss 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
    NSString *dateString = [formatter stringFromDate:datenow];
    return dateString;
    
}

//获取当前时间戳

+ (NSString *)currentTimeStr{
    //获取当前时间0秒后的时间
    NSDate* date = [NSDate dateWithTimeIntervalSinceNow:0];
    // *1000 是精确到毫秒，不乘就是精确到秒
    NSTimeInterval time=[date timeIntervalSince1970]*1000;
    
    NSString *timeString = [NSString stringWithFormat:@"%.0f", time];
    return timeString;
    
}

// 时间戳转时间,时间戳为13位是精确到毫秒的，10位精确到秒

+ (NSString *)getDateStringWithTimeStr:(NSString *)str{
    //传入的时间戳str如果是精确到毫秒的记得要/1000
    NSTimeInterval time=[str doubleValue]/1000;
    
    NSDate *detailDate=[NSDate dateWithTimeIntervalSince1970:time];
    //实例化一个NSDateFormatter对象
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    
    //设定时间格式,这里可以设置成自己需要的格式
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss SS"];
    NSString *currentDateStr = [dateFormatter stringFromDate: detailDate];
    return currentDateStr;
    
}

//字符串转时间戳

+ (NSInteger)getTimeStrWithString:(NSString *)str{
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateStyle:NSDateFormatterMediumStyle];
    [formatter setTimeStyle:NSDateFormatterShortStyle];
    [formatter setDateFormat:@"YYYY-MM-dd HH:mm:ss 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];
    //将字符串按formatter转成nsdate
    NSDate* date = [formatter dateFromString:str];
    
    //时间转时间戳的方法:
    NSInteger timeSp = [[NSNumber numberWithDouble:[date timeIntervalSince1970]*1000] integerValue];

    return timeSp;
}


//获取两个时间的间隔
+ (long long)getDurationDateStartTime:(NSString *)startTime endTime:(NSString *)endTime {
    if (startTime && endTime) {
        NSDateFormatter *strDateStr = [[NSDateFormatter alloc]init];
        [strDateStr setDateFormat:@"YYYY-MM-dd HH:mm:ss"];
        NSDate *startdate = [strDateStr dateFromString:startTime];
        NSDate *enddate = [strDateStr dateFromString:endTime];
        //时间转时间戳的方法:
        NSTimeInterval aTime = [enddate timeIntervalSinceDate:startdate];
        return (long long)aTime;
    } else {
        return -1;
    }
}



//持续时间(时间戳取差值)
+ (long long)getDurationTimeStartTime:(NSString *)startTime endTime:(NSString *)endTime {
    if (startTime && endTime) {
        long long aTime = [endTime longLongValue] - [startTime longLongValue];
        return aTime;
    } else {
        return -1;
    }
}