- (NSDate*)dateFromString:(NSString*)dateString{

    NSDateFormatter*dateFormatter=[[NSDateFormatteralloc]init];

    [dateFormattersetDateFormat:@"yyyy-MM-ddHH:mm:ss"];

    NSDate*destDate= [dateFormatterdateFromString:dateString];

    returndestDate;

}

- (NSString*)stringFromDate:(NSDate*)date{

    NSDateFormatter*dateFormatter=[[NSDateFormatteralloc]init];

    //zzz表示时区，zzz可以删除，这样返回的日期字符将不包含时区信息。

    [dateFormattersetDateFormat:@"MM-ddHH:mm"];

    NSString*destDateString =[dateFormatter stringFromDate:date];

    returndestDateString;

}

-(NSString*)stringFromValue:(NSString*)value{

    NSDate*confromTimesp=[NSDatedateWithTimeIntervalSince1970:[valuelongLongValue]];

    NSDateFormatter*formatter=[[NSDateFormatteralloc]init];

    [formattersetDateFormat:@"MM-ddHH:mm"];

    NSString*date =[formatter stringFromDate:confromTimesp];

    returndate;

}

NSDate、NSString、long转化