NSString *dateStr=[dic objectForKey:@"date"];// 2012-05-17 11:23:23

    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

     NSUInteger unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit;

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

    [format setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

    NSDate *fromdate=[format dateFromString:dateStr];

    NSTimeZone *fromzone = [NSTimeZone systemTimeZone];

    NSInteger frominterval = [fromzone secondsFromGMTForDate: fromdate];

    NSDate *fromDate = [fromdate  dateByAddingTimeInterval: frominterval];

     NSLog(@"fromdate=%@",fromDate);

    [format release];

    NSDate *date = [NSDate date];

    NSTimeZone *zone = [NSTimeZone systemTimeZone];

    NSInteger interval = [zone secondsFromGMTForDate: date];

    NSDate *localeDate = [date  dateByAddingTimeInterval: interval];

    NSLog(@"enddate=%@",localeDate);

    NSDateComponents *components = [gregorian components:unitFlags fromDate:fromDate toDate:localeDate options:0];

    NSInteger months = [components month];

    NSInteger days = [components day];//年[components year]

    NSLog(@"month=%d",months);

    NSLog(@"days=%d",days);

    [gregorian release];

    if (months==0&&days;==0) {

        dateStr=[[dateStr substringFromIndex:11]substringToIndex:5];

        cell.textLabel.text=[NSString stringWithFormat:@"今天 %@",dateStr];//今天 11:23

    }else if(months==0&&days;==1){

        dateStr=[[dateStr substringFromIndex:11]substringToIndex:5];

        cell.textLabel.text=[NSString stringWithFormat:@"昨天 %@",dateStr];//昨天 11:23

    }else{

        dateStr=[dateStr substringToIndex:10];

        cell.textLabel.text=dateStr;

    }