RandomAccessFileTest.java

package tutorial.java;

import org.junit.Test;

import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Arrays;

public class RandomAccessFileTest {

    public static void main(String[] args) {

        int a = 34;

        System.out.println("a = " + a);
        System.out.println("args = " + Arrays.deepToString(args)); // soutp : paramters
        System.out.println("RandomAccessFileTest.main"); // soutm: method

    }

    @Test
    public void test() {


        RandomAccessFile raf1 = null;
        RandomAccessFile raf2 = null;

        try {
            raf1 = new RandomAccessFile("nature.jpg", "r");
            raf2 = new RandomAccessFile("nature1.jpg", "rw");

            int len;
            byte[] buffer = new byte[1024];
            while ((len = raf1.read(buffer)) != -1){
                raf2.write(buffer, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
                if(raf2 != null){
                    try {
                        raf2.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if(raf1 != null){
                    try {
                        raf1.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }

        }

        /*if RandomAccessFile used as an output Stream, if the des file doesn't exist, then it will create a new file,
        * if it does exist, then will cover from the beginning, like 'xyz' covers the 'abc'
        * */
    @Test
    public void test2() {

            RandomAccessFile raf2 = null;
            try {
                raf2 = new RandomAccessFile("randomTest.txt", "rw");

                raf2.seek(3); // put the index to 3
                raf2.write("xyz".getBytes());

            }catch (IOException e){
                e.printStackTrace();
            }finally {
                if(raf2 != null){
                    try {
                        raf2.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
    }

}