Lessons4JavaSE/src/unit06/TestRandomAccessFile.java at master · AlohaWorld/Lessons4JavaSE · GitHub

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package unit06;

import java.io.*;

public class TestRandomAccessFile {

public static void main(String[] args) throws IOException {

// Create a random access file

// In "rw" mode, Reading and Writing share one file pointer

RandomAccessFile inout = new RandomAccessFile("inout.dat", "rw");

// Clear the file to destroy the old contents if exists

inout.setLength(0);

// Write new integers to the file

for (int i = 0; i < 200; i++)

inout.writeInt(i);

// Display the current length of the file

System.out.println("Current file length is " + inout.length());

// Retrieve the first number

inout.seek(0); // Move the file pointer to the beginning

System.out.println("The first number is " + inout.readInt());

// Retrieve the second number

inout.seek(1 * 4); // Move the file pointer to the second number

System.out.println("The second number is " + inout.readInt());

// Retrieve the tenth number

inout.seek(9 * 4); // Move the file pointer to the tenth number

System.out.println("The tenth number is " + inout.readInt());

// Modify the eleventh number

inout.writeInt(555);

// Append a new number

inout.seek(inout.length()); // Move the file pointer to the end

inout.writeInt(999);

// Display the new length

System.out.println("The new length is " + inout.length());

// Retrieve the new eleventh number

inout.seek(10 * 4); // Move the file pointer to the eleventh number

System.out.println("The eleventh number is " + inout.readInt());

inout.close();

}

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