Converting text to and from ByteBuffers : Input Output Stream « File Input Output « Java

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Java » File Input Output » Input Output StreamScreenshots 
Converting text to and from ByteBuffers
Converting text to and from ByteBuffers


// : c12:BufferToText.java
// Converting text to and from ByteBuffers
// {Clean: data2.txt}
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.

import java.io.FileInputStream;
import java.io.FileOutputStream;
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[] argsthrows Exception {
    FileChannel fc = new FileOutputStream("data2.txt").getChannel();
    fc.write(ByteBuffer.wrap("Some text".getBytes()));
    fc.close();
    fc = new FileInputStream("data2.txt").getChannel();
    ByteBuffer buff = ByteBuffer.allocate(BSIZE);
    fc.read(buff);
    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));
    // Or, we could encode with something that will print:
    fc = new FileOutputStream("data2.txt").getChannel();
    fc.write(ByteBuffer.wrap("Some text".getBytes("UTF-16BE")));
    fc.close();
    // Now try reading again:
    fc = new FileInputStream("data2.txt").getChannel();
    buff.clear();
    fc.read(buff);
    buff.flip();
    System.out.println(buff.asCharBuffer());
    // Use a CharBuffer to write through:
    fc = new FileOutputStream("data2.txt").getChannel();
    buff = ByteBuffer.allocate(24)// More than needed
    buff.asCharBuffer().put("Some text");
    fc.write(buff);
    fc.close();
    // Read and display:
    fc = new FileInputStream("data2.txt").getChannel();
    buff.clear();
    fc.read(buff);
    buff.flip();
    System.out.println(buff.asCharBuffer());
  }
///:~


           
       
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9.Comparing Buffered and Unbuffered Writing Performance
10.Read a file and print, using LineReader and System.out
11.Demonstrate ProgressMeterInputStream
12.Demonstrates standard I/O redirection
13.Creating a very large file using mappingCreating a very large file using mapping
14.Demonstrates the use of the File class to create directories and manipulate files
15.Mapping an entire file into memory for reading
16.Mapped IOMapped IO
17.What happens when the entire file isn't in your mapping region
18.Object serializationObject serialization
19.Locking portions of a mapped fileLocking portions of a mapped file
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