// newio/GetChannel.java

// (c)2017 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

// Getting channels from streams

import java.nio.*;

import java.nio.channels.*;

import java.io.*;

public class GetChannel {

private static String name = "data.txt";

private static final int BSIZE = 1024;

public static void main(String[] args) {

// Write a file:

try(

FileChannel fc = new FileOutputStream(name)

.getChannel()

) {

fc.write(ByteBuffer

.wrap("Some text ".getBytes()));

} catch(IOException e) {

throw new RuntimeException(e);

}

// Add to the end of the file:

try(

FileChannel fc = new RandomAccessFile(

name, "rw").getChannel()

) {

fc.position(fc.size()); // Move to the end

fc.write(ByteBuffer

.wrap("Some more".getBytes()));

} catch(IOException e) {

throw new RuntimeException(e);

}

// Read the file:

try(

FileChannel fc = new FileInputStream(name)

.getChannel()

) {

ByteBuffer buff = ByteBuffer.allocate(BSIZE);

fc.read(buff);

buff.flip();

while(buff.hasRemaining())

System.out.write(buff.get());

} catch(IOException e) {

throw new RuntimeException(e);

}

System.out.flush();

}

}

/* Output:

Some text Some more

*/