// newio/BufferToText.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.

// Converting text to and from ByteBuffers

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;

import java.nio.charset.Charset;

public class BufferToText {

private static final int BSIZE = 1024;

public static void main(String[] args) {

try (

FileChannel fc = new FileOutputStream(

"data2.txt").getChannel()

) {

fc.write(ByteBuffer.wrap("Some text".getBytes()));

} catch (IOException e) {

throw new RuntimeException(e);

}

ByteBuffer buff = ByteBuffer.allocate(BSIZE);

try (

FileChannel fc = new FileInputStream(

"data2.txt").getChannel()

) {

fc.read(buff);

} catch (IOException e) {

throw new RuntimeException(e);

}

buff.flip();

// Doesn't work:

System.out.println(buff.asCharBuffer());

// Decode using this system's default Charset:

buff.rewind();

String encoding =

System.getProperty("file.encoding");

System.out.println("Decoded using " +

encoding + ": "

+ Charset.forName(encoding).decode(buff));

// Encode with something that prints:

try (

FileChannel fc = new FileOutputStream(

"data2.txt").getChannel()

) {

fc.write(ByteBuffer.wrap(

"Some text".getBytes("UTF-16BE")));

} catch (IOException e) {

throw new RuntimeException(e);

}

// Now try reading again:

buff.clear();

try (

FileChannel fc = new FileInputStream(

"data2.txt").getChannel()

) {

fc.read(buff);

} catch (IOException e) {

throw new RuntimeException(e);

}

buff.flip();

System.out.println(buff.asCharBuffer());

// Use a CharBuffer to write through:

buff = ByteBuffer.allocate(24);

buff.asCharBuffer().put("Some text");

try (

FileChannel fc = new FileOutputStream(

"data2.txt").getChannel()

) {

fc.write(buff);

} catch (IOException e) {

throw new RuntimeException(e);

}

// Read and display:

buff.clear();

try (

FileChannel fc = new FileInputStream(

"data2.txt").getChannel()

) {

fc.read(buff);

} catch (IOException e) {

throw new RuntimeException(e);

}

buff.flip();

System.out.println(buff.asCharBuffer());

}

}

/* Output:

????

Decoded using windows-1252: Some text

Some text

Some textNULNULNUL

*/