Writing a 3D array to a binary file and reading the file back into another Java 3D array

Question

I have a purpose that I have to create a 3D array of random size, write it to a binary file, then read the binary file back into the program and create another three-dimensional array that will be the same as the first one. I have problems reading back to the program, after several hours I can only get the first int or the last from the previous array. I did not go past the first 2D, but I just allocated some space to make the array work, but as soon as I get this, it should come quickly. The readData () method is the one that gives me problems. Thanks in advance.

import java.io.*; import java.util.*; public class homework1 { public homework1() { } // Allocates space for the 3-dimension array as specified and for each // array element, assigns a random number, and return the array public static int[][][] createData() { int[][][] data; //Random variables for array dimensions Random rand = new Random(); int x = rand.nextInt(5) + 1; rand = new Random(); int y = rand.nextInt(5) + 1; rand = new Random(); int z = rand.nextInt(5) + 1; data = new int[x][y][z]; for (int i = 0; i < x; i++) { for (int j = 0; j < y; j++) { for (int k = 0; k < z; k++) { rand = new Random(); int r = rand.nextInt(5) + 1; data[i][j][k] = r; } } } return data; } //Writes the 3-dimension array to file. public static int[][][] writeData(int[][][] array, String fileName) throws IOException { try { FileOutputStream out = new FileOutputStream(fileName); DataOutputStream outs = new DataOutputStream(out); for (int i = 0; i < array.length; i++) { //outs.writeInt(array[i].length); (maybe?) for (int j = 0; j < array[i].length; j++) { //outs.writeInt(array[i][j].length); (maybe?) for (int k = 0; k < array[i][j].length; k++) { outs.writeInt(array[i][j][k]); } } } outs.close(); out.close(); } catch (IOException e) { e.printStackTrace(); } return array; } public static int[][][] readData(String fileName) throws FileNotFoundException, IOException { int[][][] array = new int[3][3][5]; try { FileInputStream in = new FileInputStream(fileName); DataInputStream ins = new DataInputStream(in); int readFrom = ins.readInt(); //read 4 binary byes and System.out.println("From file"); while (in.read() != -1) { // poop = ins.readInt(); System.out.println(readFrom); for (int i = 0; i < array.length; i++) { //outs.writeInt(array[i].length); (maybe?) for (int j = 0; j < array[i].length; j++) { //outs.writeInt(array[i][j].length); (maybe?) for (int k = 0; k < array[i][j].length; k++) { array[i][j][k] = readFrom; } } } System.out.flush(); readFrom=ins.readInt(); } //save them in an integer } catch (FileNotFoundException e) { e.printStackTrace(); } catch (EOFException ex){ ex.printStackTrace(); } System.out.println("Blank array that needs to be filled"); return array; } // Displays the array. public static void printData(int[][][] array) { for (int i = 0; i < array.length; i++) { System.out.println("Frame " + i + ":"); for (int j = 0; j < array[i].length; j++) { for (int k = 0; k < array[i][j].length; k++) { System.out.print("\t" + array[i][j][k] + " "); } System.out.print("\n"); } } } public static void main(String args[]) throws IOException { // throws FileNotFoundException, IOException { int data[][][]; data = createData(); printData(data); writeData(data, "data.out"); data = readData("data.out"); printData(data); } 

}

Answer 1

As you wrote it, you do not read from the file every time you loop in the inner loop itself, and not in outer loops. Therefore, you read only once.

The call to ins.readInt () should be in the innermost loop, because you need to read every cell of the table.

Answer 2

I believe that you can achieve this using serialization.

Answer 3

Think about it. The readData () method MUST positively receive information about the size of the array from somewhere, right? writeData (), then MUST save it.

and how many times do you call readInt () in readData ()?