Reading Mixed Data from a File : FileInputStream « File « Java Tutorial

1. Java Tutorial
2. File
3. FileInputStream

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class MainClass {
  public static void main(String[] args) {
    File aFile = new File("primes.txt");
    FileInputStream inFile = null;
    try {
      inFile = new FileInputStream(aFile);
    } catch (FileNotFoundException e) {
      e.printStackTrace(System.err);
    }
    FileChannel inChannel = inFile.getChannel();
    try {
      ByteBuffer lengthBuf = ByteBuffer.allocate(8);
      while (true) {
        if (inChannel.read(lengthBuf) == -1){
          break;
        }
        lengthBuf.flip();
        int strLength = (int) lengthBuf.getDouble();
        ByteBuffer buf = ByteBuffer.allocate(2 * strLength + 8);
        if (inChannel.read(buf) == -1) {
          break;
        }
        buf.flip();
        byte[] strChars = new byte[2 * strLength];
        buf.get(strChars);
        System.out.println(strLength);
        System.out.println(ByteBuffer.wrap(strChars).asCharBuffer());
        System.out.println(buf.getLong());
        lengthBuf.clear();
      }
      inFile.close();
    } catch (IOException e) {
      e.printStackTrace(System.err);
    }
  }
}