write nio.CharBuffer to file

[Beju]

Hello, I am completely new to Java, so here goes my stupid question:) How do I write a nio.CharBuffer to a file?? I saw some examples with ByteBuffer inolved, but it's something I cannot fully understand.
Thanks in advance:)

[Norm]

What examples have you found?
Have you searched the API doc for any file writing classes that can take the contents of a CharBuffer as a source? For example what interfaces does CharBuffer implement? Are any of those used as a source for a class that will write?
You'll probably have to write your own code to read from the CharBuffer and write to the file.

[Beju]

Examples like that:

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class MainClass {

  public static void main(String[] args) throws Exception {
    FileChannel fc = new FileOutputStream("data2.txt").getChannel();
    ByteBuffer buff = ByteBuffer.allocate(24); // More than needed
    buff.asCharBuffer().put("Some text");
    fc.write(buff);
    fc.close();

    fc = new FileInputStream("data2.txt").getChannel();
    buff.clear();
    fc.read(buff);
    buff.flip();
    System.out.println(buff.asCharBuffer());

  }
}
/*  */

Yes I've searched through the documentation, but none of the nio write()'s uses CharBuffer as a source, only ByteBuffers are supported. It's strange for me, they made a whole New IO Library, buffers for multiple data types, but You can write ony ByteBuffer :/
I wonder why It's so complicated, and also there is no function which returns size of a data structure in bytes, or maybe I didn't found it yet, but in order to make a new ByteBuffer from another [Char,Int,Float, etc...]Buffer You have to multiply the it's size by the sizeof(datatype) during allocation. Isn't it kind of.... stupid?
But You're right, I can still use a set of loops to write single character at a time:) It's like good old C...:)
Anyway, thx for interest:)

[Norm]

After looking at the doc for a while, I was wondering
How did you get data into a CharBuffer?

To write contents of a CharBuffer do something like the following to get the data into a ByteBuffer and then use your code from above:

    String text = "CB text 3";
    CharBuffer cb = CharBuffer.allocate(text.length());
    cb.put(text);
    cb.flip();
/*
    char[] carray = cb.array();
    System.out.println("hasArray() = " + cb.hasArray() +", length="+ carray.length);
    System.out.print("array=");
    for (int i = 0; i < carray.length; i++) {
      System.out.print(carray[i]);
    }
    System.out.println("");
    System.out.flush();
*/
    Charset cs = Charset.defaultCharset(); // 1.5
    System.out.println("cs= " + cs);  //cs= windows-1252
    CharsetEncoder cse = cs.newEncoder(); 
    System.out.println("cse= " + cse);  //cse= sun.nio.cs.MS1252$Encoder@19821f
    ByteBuffer buff = cse.encode(cb);   // output is 1 byte/char
    System.out.println("buff=" + buff); //buff=java.nio.HeapByteBuffer[pos=0 lim=9 cap=9]

[Beju]

After looking at the doc for a while, I was wondering
How did you get data into a CharBuffer?

I would happily tell You, but I don't know:) My task is just to write a function which saves the content of a CharBuffer into a file:)

Thanks for the code, but it's reaaally complicated to me...:confused: Java I/O is very strange....

[Norm]

Ask the one that gave you the task,how he is putting data into a CharBuffer and also why instead of into a class that has easy to output methods.

The code I gave shows how to copy a CharBuffer into a ByteBuffer. The code you posted shows how to write a ByteBuffer into a file.