Deserializing an Object - Java File Path IO

Java examples for File Path IO:Serialization

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Description

Deserializing an Object

Demo Code

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;

public class Main {
  public void m() {
    try {/*from w ww  .j  a  v  a  2s  .  c  om*/
      // Deserialize from a file
      File file = new File("filename.ser");
      ObjectInputStream in = new ObjectInputStream(new FileInputStream(file));
      // Deserialize the object
      javax.swing.JButton button = (javax.swing.JButton) in.readObject();
      in.close();

      // Get some byte array data
      byte[] bytes = getBytesFromFile(file);

      // Deserialize from a byte array
      in = new ObjectInputStream(new ByteArrayInputStream(bytes));
      button = (javax.swing.JButton) in.readObject();
      in.close();
    } catch (ClassNotFoundException e) {
    } catch (IOException e) {
    }
  }

  // Returns the contents of the file in a byte array.
  public static byte[] getBytesFromFile(File file) throws IOException {
    InputStream is = new FileInputStream(file);

    // Get the size of the file
    long length = file.length();

    if (length > Integer.MAX_VALUE) {
      // File is too large
    }

    // Create the byte array to hold the data
    byte[] bytes = new byte[(int) length];

    // Read in the bytes
    int offset = 0;
    int numRead = 0;
    while (offset < bytes.length
        && (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
      offset += numRead;
    }

    // Ensure all the bytes have been read in
    if (offset < bytes.length) {
      throw new IOException("Could not completely read file " + file.getName());
    }

    is.close();
    return bytes;
  }
}

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