Use RandomAccessFile to save and read : RandomAccessFile « File « Java Tutorial






import java.io.IOException;
import java.io.RandomAccessFile;

public class MainClass {
  public static void main(String[] args) throws IOException {
    RandomAccessFile rf = new RandomAccessFile("test.dat", "rw");
    for (int i = 0; i < 10; i++)
      rf.writeDouble(i * 1.414);
    rf.close();
    rf = new RandomAccessFile("test.dat", "rw");
    rf.seek(5 * 8);
    rf.writeDouble(47.0001);
    rf.close();
    rf = new RandomAccessFile("test.dat", "r");
    for (int i = 0; i < 10; i++)
      System.out.println("Value " + i + ": " + rf.readDouble());
    rf.close();

  }
}








11.40.RandomAccessFile
11.40.1.RandomAccessFile Introduction
11.40.2.Employs RandomAccessFile to store ints and changes the value of the third int.
11.40.3.Seek in RandomAccessFile
11.40.4.Getting FileChannel from RandomAccessFile
11.40.5.Write int to RandomAccessFile using FileChannel
11.40.6.Use RandomAccessFile to save and read
11.40.7.Use RandomAccessFile to reverse a file
11.40.8.Test file pointer manipulation between FileChannel and RandomAccessFile objects.
11.40.9.Appending data to existing file