Tutorial

Via Java Serialization you can stream your Java object to a sequence of byte and restore these objects from this stream of bytes. To make a Java object serializable you implement the java.io.Serializable interface. This is only a marker interface which tells the platform that the object is serializable.

Certain system-level classes such as Thread, OutputStream and its subclasses, and Socket are not serializable. If you serializable class contains such objects, it must mark then as "transient".

Create a Java project called "de.vogella.java.serilization". Create the following Java object called "Person".

			
package de.vogella.java.serilization;

import java.io.Serializable;

public class Person implements Serializable {
	private String firstName;
	private String lastName;
	// stupid example for transient
	transient private Thread myThread;

	public Person(String firstName, String lastName) {
		this.firstName = firstName;
		this.lastName = lastName;
		this.myThread = new Thread();
	}

	public String getFirstName() {
		return firstName;
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}

	public String getLastName() {
		return lastName;
	}

	public void setLastName(String lastName) {
		this.lastName = lastName;
	}

	@Override
	public String toString() {
		return "Person [firstName=" + firstName + ", lastName=" + lastName
				+ "]";
	}

}

		

The following code example show you how you can serializable and de-serializable this object.

			
package de.vogella.java.serilization;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class Main {
	public static void main(String[] args) {
		String filename = "time.ser";
		Person p = new Person("Lars", "Vogel");

		// Save the object to file
		FileOutputStream fos = null;
		ObjectOutputStream out = null;
		try {
			fos = new FileOutputStream(filename);
			out = new ObjectOutputStream(fos);
			out.writeObject(p);

			out.close();
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		// Read the object from file
		// Save the object to file
		FileInputStream fis = null;
		ObjectInputStream in = null;
		try {
			fis = new FileInputStream(filename);
			in = new ObjectInputStream(fis);
			p = (Person) in.readObject();
			out.close();
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		System.out.println(p);
	}
}

		

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