java - How to read a file from JAR using NIO?

Question

Reading a file from the executable JAR file itself using ClassLoader.getResourceAsStream(...) is a known concept to me, but how would I do the same using Java NIO?

The target is to have a function as follows:

static String readFullyFromJar(String filename) {
    final Path path = Paths.get(Main.class.getResource(fileName).toURI());
    final byte[] bytes = Files.readAllBytes(path);
    return new String(bytes, CHARSET_ASCII);
}

While this works fine in the IDE, I get a

java.nio.file.FileSystemNotFoundException
    at com.sun.nio.zipfs.ZipFileSystemProvider.getFileSystem(ZipFileSystemProvider.java:171))

when I try this with the real JAR, even though the target file is in the correct place.

Answer 1

事实证明，我上面的代码实际上是正确的，问题在于 Java 本身。

根据这个Bug ID，Java 没有正确使用 ZipFileSystemProvider。应该在 Java 8 中修复。（我的实际问题在此重复报告中描述）