Java access files in jar causes java.nio.file.FileSystemNotFoundException

Question

While trying to copy some files in my jar file to a temp directory with my java app, the following exception is thrown:

java.nio.file.FileSystemNotFoundException
    at com.sun.nio.zipfs.ZipFileSystemProvider.getFileSystem(ZipFileSystemProvider.java:171)
    at com.sun.nio.zipfs.ZipFileSystemProvider.getPath(ZipFileSystemProvider.java:157)
    at java.nio.file.Paths.get(Unknown Source)
    at com.sora.util.walltoggle.pro.WebViewPresentation.setupTempFiles(WebViewPresentation.java:83)
   ....

and this is a small part of my setupTempFiles(with line numbers):

81. URI uri = getClass().getResource("/webViewPresentation").toURI();
//prints: URI->jar:file:/C:/Users/Tom/Dropbox/WallTogglePro.jar!/webViewPresentation
82. System.out.println("URI->" + uri );
83. Path source = Paths.get(uri);

the webViewPresentation directory resides in the root directory of my jar:

This problem only exits when I package my app as a jar, debugging in Eclipse has no problems. I suspect that this has something to do with this bug but I'm not sure how to correct this problem.

Any helps appreciated

If matters:

I'm on Java 8 build 1.8.0-b132

Windows 7 Ult. x64

Answer 1

A FileSystemNotFoundException means the file system cannot be created automatically; and you have not created it here.

Given your URI, what you should do is split against the !, open the filesystem using the part before it and then get the path from the part after the !:

final Map<String, String> env = new HashMap<>();
final String[] array = uri.toString().split("!");
final FileSystem fs = FileSystems.newFileSystem(URI.create(array[0]), env);
final Path path = fs.getPath(array[1]);

Note that you should .close() your FileSystem once you're done with it.