Reading into a Large Buffer through FileChannel : FileInputStream « File « Java Tutorial

1. Java Tutorial
2. File
3. FileInputStream

import java.io.File;
import java.io.FileInputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
public class MainClass {
  public static void main(String[] args) {
    try {
      test();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  private static void test() throws Exception {
    File aFile = new File("primes.txt");
    FileInputStream inFile = new FileInputStream(aFile);
    FileChannel inChannel = inFile.getChannel();
    ByteBuffer buf = ByteBuffer.allocateDirect(1024);
    buf.position(buf.limit());
    while (true) {
      if (buf.remaining() < 8) {
        if (inChannel.read(buf.compact()) == -1){
          break;
        }
        buf.flip();
      }
      int strLength = (int) buf.getDouble();
      if (buf.remaining() < 2 * strLength) {
        if (inChannel.read(buf.compact()) == -1){
          break;
        }
        buf.flip();
      }
      byte[] strChars = new byte[2 * strLength];
      buf.get(strChars);
      if (buf.remaining() < 8) {
        if (inChannel.read(buf.compact()) == -1){
          break;
        }
        buf.flip();
      }
      System.out.println(strLength);
      System.out.println(ByteBuffer.wrap(strChars).asCharBuffer());
      System.out.println(buf.getLong());
    }
    inFile.close();
  }
}