iOS- 时间和时间戳及与字符串转化

1.获取当前时间

- (NSString *)currentDateStr{
    NSDate *currentDate = [NSDate date];//获取当前时间，日期
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];// 创建一个时间格式化对象
    [dateFormatter setDateFormat:@"YYYY/MM/dd hh:mm:ss SS "];//设定时间格式,这里可以设置成自己需要的格式
    NSString *dateString = [dateFormatter stringFromDate:currentDate];//将时间转化成字符串
    return dateString;
}

2.获取当前时间戳

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

3.时间戳转时间

// 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{
    NSTimeInterval time=[str doubleValue]/1000;//传入的时间戳str如果是精确到毫秒的记得要/1000
    NSDate *detailDate=[NSDate dateWithTimeIntervalSince1970:time];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; //实例化一个NSDateFormatter对象
    //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;
}

4.字符串转时间戳

- (NSString *)getTimeStrWithString:(NSString *)str{
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];// 创建一个时间格式化对象
    [dateFormatter setDateFormat:@"YYYY-MM-dd HH:mm:ss"]; //设定时间的格式
    NSDate *tempDate = [dateFormatter dateFromString:str];//将字符串转换为时间对象
    NSString *timeStr = [NSString stringWithFormat:@"%ld", (long)[tempDate timeIntervalSince1970]*1000];//字符串转成时间戳,精确到毫秒*1000
    return timeStr;

5.时间戳转化为字符转

///时间戳转化为字符转0000-00-00 00:00

+ (NSString *)time_timestampToString:(NSInteger)timestamp{
    NSDate *confromTimesp = [NSDate dateWithTimeIntervalSince1970:timestamp];
    NSDateFormatter *dateFormat=[[NSDateFormatter alloc]init];
     [dateFormat setDateFormat:@"yyyy-MM-dd HH:mm"];
    NSString* string=[dateFormat stringFromDate:confromTimesp];
    return string;
}

6.date转化为字符串

//date转化为字符转0000-00-00 00:00
+ (NSString *)time_dateToString:(NSDate *)date{
    NSDateFormatter *dateFormat=[[NSDateFormatter alloc]init];
    [dateFormat setDateFormat:@"yyyy-MM-dd HH:mm"];
    NSString* string=[dateFormat stringFromDate:date];
    return string;
}

7.计算时间差

- (void)dateDifferenceValue{
    NSString *time2 = @"2018-02-11 00:00:00";
    // 2.将时间转换为date
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    formatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";
    NSDate *date1 = [NSDate date];
    NSDate *date2 = [formatter dateFromString:time2];
    // 3.创建日历
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSCalendarUnit type = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
    // 4.利用日历对象比较两个时间的差值
    NSDateComponents *cmps = [calendar components:type fromDate:date1 toDate:date2 options:0];
    // 5.输出结果
    NSLog(@"两个时间相差%ld年%ld月%ld日%ld小时%ld分钟%ld秒", cmps.year, cmps.month, cmps.day, cmps.hour, cmps.minute, cmps.second);
}