iOS文件创建

 NSString * docsdir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *dataFilePath = [docsdir stringByAppendingPathComponent:@"head"]; // 在指定目录下创建 "head" 文件夹
NSString *dataFilePath1 =    [dataFilePath stringByAppendingPathComponent:@"head22"];
NSFileManager *fileManager = [NSFileManager defaultManager];

BOOL isDir = NO;
// fileExistsAtPath 判断一个文件或目录是否有效，isDirectory判断是否一个目录
BOOL existed = [fileManager fileExistsAtPath:dataFilePath1 isDirectory:&isDir];

if ( !(isDir == YES && existed == YES) ) {
    // 在 Document 目录下创建一个 head 目录
    [fileManager createDirectoryAtPath:dataFilePath1 withIntermediateDirectories:YES attributes:nil error:nil];
}
NSString *buildPath=[[NSBundle mainBundle]pathForResource:@"V20331-172934" ofType:@"mp4"];

NSString *path=[NSString stringWithFormat:@"%@.mp4",@"path12uuuu"];
NSString *dataFilePath2 =    [dataFilePath1 stringByAppendingPathComponent:path];


NSString *content=@"write data into myFile";
NSData *contentData=[buildPath dataUsingEncoding:NSASCIIStringEncoding];
if ([contentData writeToFile:dataFilePath2 atomically:YES]) {
    NSLog(@">>write is ok.");
}