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];
}