使用nio遍历目录结构时将文件读入内存

Question

如何使用Java NIO在目录树中读取文件到内存中？

以下代码是我的第一次尝试：

String dirStart = "/start/directory/";

Path root = Paths.get(dirStart);
Files.walkFileTree(root.toAbsolutePath().normalize(), new SimpleFileVisitor<Path>() {
    @Override
    public FileVisitResult visitFile(Path file, java.nio.file.attribute.BasicFileAttributes attrs) throws IOException {
    System.out.println(file);
    String[] dirs = file.toString().split("/");
    String var1 = dirs[2];String var2 = dirs[3];String var3 = dirs[4];
    System.out.println("var1 is: "+var1);
    System.out.println("var2 is: "+var2);
    System.out.println("var3 is: "+var3);
    BufferedReader bufferedReader = null;
    try {
        InputStream inputStream = Files.newInputStream(file);
        bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        System.out.println("Reading Line: " + bufferedReader.readLine());
        } catch (IOException e) {e.printStackTrace();
    }
    finally {
        try {bufferedReader.close();}
        catch (IOException ioe) {ioe.printStackTrace();}
    }
    return FileVisitResult.CONTINUE;
    }
});  

但是以下行抛出空指针错误：

try {bufferedReader.close();}

也许问题可能是上面的代码混合了java.nio和java.io，但我该如何解决？

答案：

根据SotiriosDelimanolis的建议，我尝试嵌套try-with-resources语句，并获得以下代码，解决了这个问题并回答了这个问题：

Path root = Paths.get(dirStart);
Files.walkFileTree(root.toAbsolutePath().normalize(), new SimpleFileVisitor<Path>() {
    @Override
    public FileVisitResult visitFile(Path file, java.nio.file.attribute.BasicFileAttributes attrs) throws IOException {
        try(InputStream inputStream = Files.newInputStream(file);BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream))){
            System.out.println("Reading Line: " + bufferedReader.readLine());
        } catch (IOException e) {e.printStackTrace();}
    return FileVisitResult.CONTINUE;
}
});