这些时间从API解析下来的时间格式都为 yyyy-MM-dd HH:mm:ss(比如:2013-03-09 09:51:22),通过在API上获取文章时间后经过算法转换而得到，在客户端源码的Tool.m中+ (NSString *)intervalSinceNow: (NSString *) theDate 实现这一个方法: 如果信息发表在1小时之前显示分钟，一天之内的信息显示小时，10天之内按天显示，10天之外安所发表时间进行显示： source:http://blog.csdn.net/duxinfeng2010/article/details/8653411

nsdate.m

+ (NSString *)intervalSinceNow: (NSString *) theDate 
{
    NSDateFormatter *date=[[NSDateFormatter alloc] init];
    [date setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSDate *d=[date dateFromString:theDate];
    NSTimeInterval late=[d timeIntervalSince1970]*1;
    NSDate* dat = [NSDate dateWithTimeIntervalSinceNow:0];
    NSTimeInterval now=[dat timeIntervalSince1970]*1;
    NSString *timeString=@"";
    NSTimeInterval cha=now-late;
//    发表在一小时之内
    if (cha/3600<1) {
        if (cha/60<1) {
            timeString = @"1";
        }
        else
        {
            timeString = [NSString stringWithFormat:@"%f", cha/60];
            timeString = [timeString substringToIndex:timeString.length-7];
        }
        
        timeString=[NSString stringWithFormat:@"%@分钟前", timeString];
    }
//    在一小时以上24小以内
    else if (cha/3600>1&&cha/86400<1) {
        timeString = [NSString stringWithFormat:@"%f", cha/3600];
        timeString = [timeString substringToIndex:timeString.length-7];
        timeString=[NSString stringWithFormat:@"%@小时前", timeString];
    }
//    发表在24以上10天以内
    else if (cha/86400>1&&cha/864000<1)
    {
        timeString = [NSString stringWithFormat:@"%f", cha/86400];
        timeString = [timeString substringToIndex:timeString.length-7];
        timeString=[NSString stringWithFormat:@"%@天前", timeString];
    }
//    发表时间大于10天
    else
    {
//        timeString = [NSString stringWithFormat:@"%d-%"]
        NSArray *array = [theDate componentsSeparatedByString:@" "];
//        return [array objectAtIndex:0];
        timeString = [array objectAtIndex:0];
    }
    return timeString;
}


//改良版
- (NSString *)intervalSinceNow
{
    NSDateFormatter *date=[[NSDateFormatter alloc] init];
    [date setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    
    NSTimeInterval timeInterval=[self timeIntervalSince1970]*1;
    
    NSDate* dat = [NSDate dateWithTimeIntervalSinceNow:0];
    NSTimeInterval now=[dat timeIntervalSince1970]*1;
    
    NSString *timeString=@"";
    NSTimeInterval cha=now-timeInterval;
    //    发表在一小时之内
    if (cha/3600<1) {
        if (cha/60<1) {
            timeString = @"刚刚";
        }
        else
        {
            timeString = [NSString stringWithFormat:@"%f", cha/60];
            timeString = [timeString substringToIndex:timeString.length-7];
            timeString=[NSString stringWithFormat:@"%@分钟前", timeString];
        }
        
    }
    //    在一小时以上24小以内
    else if (cha/3600>1&&cha/86400<1) {
        timeString = [NSString stringWithFormat:@"%f", cha/3600];
        timeString = [timeString substringToIndex:timeString.length-7];
        timeString=[NSString stringWithFormat:@"%@小时前", timeString];
    }
    //    发表在24以上10天以内
    else if (cha/86400>1&&cha/864000<1)
    {
        timeString = [NSString stringWithFormat:@"%f", cha/86400];
        timeString = [timeString substringToIndex:timeString.length-7];
        timeString=[NSString stringWithFormat:@"%@天前", timeString];
    }
    //    发表时间大于10天
    else
    {
        NSArray *array = [[date stringFromDate:self] componentsSeparatedByString:@" "];
        timeString = [array objectAtIndex:0];
    }
    return timeString;
}