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];
 }