OnJava8-Examples/serialization/SerialCtl.java

// serialization/SerialCtl.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// Controlling serialization by adding your own
// writeObject() and readObject() methods
import java.io.*;

public class SerialCtl implements Serializable {
  private String a;
  private transient String b;
  public SerialCtl(String aa, String bb) {
    a = "Not Transient: " + aa;
    b = "Transient: " + bb;
  }
  @Override public String toString() {
    return a + "\n" + b;
  }
  private void writeObject(ObjectOutputStream stream)
  throws IOException {
    stream.defaultWriteObject();
    stream.writeObject(b);
  }
  private void readObject(ObjectInputStream stream)
  throws IOException, ClassNotFoundException {
    stream.defaultReadObject();
    b = (String)stream.readObject();
  }
  public static void main(String[] args) {
    SerialCtl sc = new SerialCtl("Test1", "Test2");
    System.out.println("Before:\n" + sc);
    try (
      ByteArrayOutputStream buf =
        new ByteArrayOutputStream();
      ObjectOutputStream o =
        new ObjectOutputStream(buf);
    ) {
      o.writeObject(sc);
      // Now get it back:
      try (
        ObjectInputStream in =
          new ObjectInputStream(
            new ByteArrayInputStream(
              buf.toByteArray()));
      ) {
        SerialCtl sc2 = (SerialCtl)in.readObject();
        System.out.println("After:\n" + sc2);
      }
    } catch(IOException | ClassNotFoundException e) {
      throw new RuntimeException(e);
    }
  }
}
/* Output:
Before:
Not Transient: Test1
Transient: Test2
After:
Not Transient: Test1
Transient: Test2
*/