在ios中的Document中创建多级文件夹以及文件

- (NSString *)dataPath:(NSString *)file{        NSString *path = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"badge"];    BOOL bo = [[NSFileManager defaultManager] createDirectoryAtPath:path withIntermediateDirectories:YES attributes:nil error:nil];    NSAssert(bo,@"创建目录失败");        NSString *result = [path stringByAppendingPathComponent:file];        return result;    } - (void)viewDidLoad{    [super viewDidLoad];     //此处首先指定了图片存取路径（默认写到应用程序沙盒 中）    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);       //并给文件起个文件名    NSString *imageDir = [[[paths objectAtIndex:0] stringByAppendingPathComponent:@"163"] stringByAppendingPathComponent:@"songzi"];        //存放图片的文件夹    NSString *imagePath =[imageDir stringByAppendingPathComponent:@"0.png"];        NSData *data = nil;        //检查图片是否已经保存到本地    if([self isExistsFile:imagePath]){        data=[NSData dataWithContentsOfFile:imagePath];    }else{        data = [NSData dataWithContentsOfURL:[NSURL URLWithString: @"http://211.154.154.96:7071/press/163/songzi/0.jpg"]];                //创建文件夹路径        [[NSFileManager defaultManager] createDirectoryAtPath:imageDir withIntermediateDirectories:YES attributes:nil error:nil];                //创建图片        [UIImagePNGRepresentation([UIImage imageWithData:data]) writeToFile:imagePath atomically:YES];             }    imageView.image = [UIImage imageWithData:data];}