iOS文件管理 NSFileManager NSFileHandle

http://liuxing8807.blog.163.com/blog/static/9703530520133413353291/

http://www.cnblogs.com/jay-dong/archive/2013/01/21/2870414.html

Should noted:   http://useyourloaf.com/blog/2011/06/12/nsfilemanager-defaultmanager-is-not-thread-safe.html

NSFileManager *fileManager = [NSFileManager defaultManager];

if ([fileManager fileExistsAtPath:sourceFile]) {

  NSError *error = nil;

  if (![fileManager copyItemAtPath:sourceFile

                            toPath:destFile

                             error:&error]) {

    // Deal with error

  }

}

The methods of the shared NSFileManager object can be called from multiple threads safely. However, if you use a delegate to receive notifications about the status of move, copy, remove, and link operations, you should create a unique instance of the file manager object, assign your delegate to that object, and use that file manager to initiate your operations.

In iOS and Mac OS X v 10.5 and later you should consider using [[NSFileManager alloc] init] rather than the singleton method defaultManager. Instances ofNSFileManager are considered thread-safe when created using [[NSFileManager alloc] init].

This means that if your application ends up using the NSFileManager singleton from more than one thread you may get some unexpected results or even end up with corrupted files in your file system. The thread safe version of the above code fragment would look like this:

NSFileManager *fileManager = [[NSFileManager alloc] init];

if ([fileManager fileExistsAtPath:sourceFile]) {

  NSError *error = nil;

  if (![fileManager copyItemAtPath:sourceFile

                            toPath:destFile

                             error:&error]) {

    // Deal with error

  }

}

[fileManager release];