Question

Recently I got a comment to this answer that I should stay away from java.io if I want to use "pure NIO".
This is the simplified code (copy a file):

private static void copy(File source, File destination) throws IOException {
    long length = source.length();
    FileChannel input = new FileInputStream(source).getChannel();
    FileChannel output = new FileOutputStream(destination).getChannel();

    input.transferTo(0, length, output);

    output.close();
    input.close();
}

^{(code extremely simplified: removed try-finally and loop)}

My question is how to get a FileChannel or other NIO class for reading a file without using java.io (FileInputStream)?

EDIT:
Java 6 (or before only)

Answer 1

The javadoc of FileChannel says:

This class does not define methods for opening existing files or for creating new ones; such methods may be added in a future release. In this release a file channel can be obtained from an existing FileInputStream, FileOutputStream, or RandomAccessFile object by invoking that object s getChannel method, which returns a file channel that is connected to the same underlying file.

That is, with java 1.6 you can t get a FileChannel without using old java.io.

Answer 2

Java 6 only has FileInputStream.getChannel(), FileOutputStream.getChannel(), and RandomAccessFile.getChannel()

Java 7 has java.nio.channels.FileChannel.open(...) and java.nio.Files.newByteChannel(...)

友情链接