Serialize and DeSerialize object in java - An explanation Full programs


In order to serialize object our class needs to implement java.io.Serializable interface. Serializable interface is Marker interface i.e. it does not have any methods of its own, but it tells Jvm that object has to converted into byte stream.




SERIALIZATION>
Create object of ObjectOutput and give its reference variable name oout and call writeObject() method and pass our employee object as parameter [oout.writeObject(object1) ]


OutputStream fout = new FileOutputStream("ser.txt");
ObjectOutput oout = new ObjectOutputStream(fout);
System.out.println("Serialization process has started, serializing employee objects...");
oout.writeObject(object1);


Full Program/SourceCode to Serialize Object>
package SerDeser1;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;

/** Copyright (c), AnkitMittal JavaMadeSoEasy.com */

/*Author : AnkitMittal  Copyright- contents must not be reproduced in any form*/
class Employee implements Serializable {
  
   private static final long serialVersionUID = 1L;
   private Integer id;
   private String name;
   public Employee(Integer id, String name) {
          this.id = id;
          this.name = name;
   }
   @Override
   public String toString() {
          return "Employee [id=" + id + ", name=" + name + "]";
   }
}
public class SerializeEmployee {
   public static void main(String[] args) {
          Employee object1 = new Employee(1, "amy");
          Employee object2 = new Employee(2, "ankit");
          try {
                 OutputStream fout = new FileOutputStream("ser.txt");
                 ObjectOutput oout = new ObjectOutputStream(fout);
                 System.out.println("Serialization process has started, serializing employee objects...");
                 oout.writeObject(object1);
                 oout.writeObject(object2);
                   oout.close();
                 System.out.println("Object Serialization completed.");
                
          } catch (IOException ioe) {
                 ioe.printStackTrace();
          }
   }
}
/*OUTPUT
Serialization process has started, serializing employee objects...
Object Serialization completed.
*/



DESERIALIZATION>
Create object of ObjectInput and give it’s reference variable name oin and call readObject() method [oin.readObject() ]

InputStream fin=new FileInputStream("ser.txt");
ObjectInput oin=new ObjectInputStream(fin);
System.out.println("DeSerialization process has started, displaying employee objects...");
Employee emp;
emp=(Employee)oin.readObject();


Full Program/SourceCode to DeSerialize object>
import java.io.EOFException;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInput;
import java.io.ObjectInputStream;
/** Copyright (c), AnkitMittal JavaMadeSoEasy.com */
/*Author : AnkitMittal  Copyright- contents must not be reproduced in any form*/
public class DeSerializeEmployee {
   public static void main(String[] args) {
          InputStream fin;
          try {
                 fin = new FileInputStream("ser.txt");
                 ObjectInput oin = new ObjectInputStream(fin);
                 System.out.println("DeSerialization process has started, "
                              + "displaying employee objects...");
                 Employee emp;
                 while ((emp = (Employee) oin.readObject()) != null) {
                       System.out.println(emp);
                 }
                 oin.close();
          } catch (EOFException e) {
                 System.out.println("File ended");
          }  catch (FileNotFoundException e) {
                 e.printStackTrace();
          } catch (IOException e) {
                 e.printStackTrace();
          } catch (ClassNotFoundException e) {
                 e.printStackTrace();
          }
          System.out.println("Object DeSerialization completed.");
   }
}
/*OUTPUT
DeSerialization process has started, displaying employee objects...
Employee [id=1, name=amy]
Employee [id=2, name=ankit]
File ended
Object DeSerialization completed.
*/

In the above program when file is read till end using readObject() in while loop then EOFException is thrown. Java Api doesn’t provide any elegant solution to signify end the file. Please read this post where we’ll discuss the best possible solution to address the problem : Avoid ObjectInputStream.readObject() from throwing EOFException at End Of File in java



RELATED LINKS>

Serialization And Deserialization Tutorial


Serializing & DeSerializing >


Customizing  Serialization process >



serialVersionUID  >

Interviews >



Also Read :

Core Java tutorial in detail


Collection framework Tutorial in java in detail with diagrams and programs


Exceptions Tutorial in java in detail with diagrams and programs


Thread Concurrency Tutorial


No comments:

Post a Comment