Serializing Variations on an Object : Object Serialization « File « Java Tutorial





import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

class Data implements Serializable {
  private int value;
  public Data(int init) {
    value = init;
  }
  public boolean equals(Object obj) {
    if (obj instanceof Data && ((Data) obj).value == value) {
      return true;
    }
    return false;
  }
  public void setValue(int val) {
    value = val;
  }
  public int getValue() {
    return value;
  }
}
public class MainClass {
  public static void main(String[] args) {
    Data data = new Data(1);
    try {
      ObjectOutputStream objectOut = new ObjectOutputStream(new BufferedOutputStream(
          new FileOutputStream("C:/test.bin")));
      objectOut.writeObject(data);
      System.out.println("1st Object written has value: " + data.getValue());
      data.setValue(2);
      objectOut.writeObject(data);
      System.out.println("2nd Object written has value: " + data.getValue());
      data.setValue(3);
      objectOut.writeObject(data);
      System.out.println("3rd Object written has value: " + data.getValue());
      objectOut.close();
    } catch (IOException e) {
      e.printStackTrace(System.err);
    }
    try {
      ObjectInputStream objectIn = new ObjectInputStream(new BufferedInputStream(
          new FileInputStream("C:/test.bin")));
      Data data1 = (Data) objectIn.readObject();
      Data data2 = (Data) objectIn.readObject();
      Data data3 = (Data) objectIn.readObject();
      System.out.println(data1.equals(data2));
      System.out.println(data2.equals(data3));
      System.out.println(data1.getValue());
      System.out.println(data2.getValue());
      System.out.println(data3.getValue());
      objectIn.close();
    } catch (Exception e) {
      e.printStackTrace(System.err);
    }
  }
}
1st Object written has value: 1
2nd Object written has value: 2
3rd Object written has value: 3
true
true
1
1
1










11.38.Object Serialization
11.38.1.Conditions for Serialization
11.38.2.Storing Objects in a File
11.38.3.Reading an Object From a File
11.38.4.Serializing Variations on an Object
11.38.5.Writing objects sequentially to a file with class ObjectOutputStream
11.38.6.Read a file of objects sequentially and displays each record
11.38.7.Only parent class is Serializable
11.38.8.Saving and restoring the state of classes
11.38.9.Class combination Serialization
11.38.10.Controlling serialization by adding your own
11.38.11.Serialization with ObjectInputStream and ObjectOutputStream
11.38.12.Deal with transient in Object Serialization
11.38.13.Serialization Utilities