时间转换

-(NSString*)time:(NSString*)num{

    NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init];
    [inputFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]];
    [inputFormatter setDateFormat:@"yyyyMMdd"];
    NSDate* inputDate = [inputFormatter dateFromString:num];
    
    NSDateFormatter *outputFormatter = [[NSDateFormatter alloc] init];
    [outputFormatter setLocale:[NSLocale currentLocale]];
    [outputFormatter setDateFormat:@"yyyy年MM月dd日"];
    NSString *str = [outputFormatter stringFromDate:inputDate];
    return str;
}