Java - Serialization

1. Java - Primitives
2. Java - Strings
3. Java - Arrays
4. Java - Date
5. Java - Generics
6. Java - Collections
7. Java - Localization
8. Java - Formatting
9. Java - Regular Expressions
10. Java - System
11. Java - Serialization
12. Java - Multithreading
13. Java - IO/File
14. Java - Networking
15. Java - ORM - JPA
      a) Simple User entity class

package basics.basicsExamples;

import java.io.*;
import java.util.logging.Level;
import java.util.logging.Logger;

/** ****************************************************************************
 * SERIALIZATION EXAMPLE CLASS
 * 
 * http://java.sun.com/developer/technicalArticles/Programming/serialization/
 * 
 * @author stanislav.zorjan
 */
public class SerializationExample {

    
    private String fileName = "serialization.ser";
    private SimpleSerializedClass ssc;

    
    
    /** ************************************************************************
     * Default constructor
     */
    public SerializationExample() {
	ssc = new SimpleSerializedClass();
	ssc.setString("Serialized String");
	ssc.notSerializedString = "Serialize this string";
	
	// serializing object
	serializeObject(ssc);
	
	// deserializing object
	ssc = (SimpleSerializedClass) deserializeObject(this.fileName);
	
	// reading from deserialized object
	System.out.println("String from deserialized object: "+ssc.getString());
	System.out.println("Transient string from deserialized object: "+ssc.notSerializedString);
    }
    
    
    /** ************************************************************************
     * Serialization method
     * @param  Object for serialization
     * @param  
     * @param t 
     */
    private  void serializeObject(T t){
	FileOutputStream fos;
	ObjectOutputStream oos;
	    
	try{
	    fos = new FileOutputStream(this.fileName);
	    oos = new ObjectOutputStream(fos);
	    oos.writeObject(t);
	    oos.close();
	    System.out.println("Object successfully serialized");
	    System.out.println("");
	}catch(IOException ex){
	    ex.printStackTrace();
	}
    }
    
    
    
    /** ************************************************************************
     * De-serialization method
     * @param fileName
     * @return 
     */
    private Object deserializeObject(String fileName){
	
	FileInputStream fis;
	ObjectInputStream ois = null;
	Object obj = null;
	
	try{
	    fis = new FileInputStream(fileName);
	    ois = new ObjectInputStream(fis);
	    obj = ois.readObject();
	}catch(IOException ex){
	    ex.printStackTrace();
	}catch(ClassNotFoundException ex){
	    ex.printStackTrace();
	}
	
	return obj;
    }
}



/** ****************************************************************************
 * SERIALIZABLE CLASS
 * @author stanislav.zorjan
 */
class SimpleSerializedClass implements Serializable,SimpleInterface {

    private String str;
    
    // nonserializable object/field.
    // when deserialized, field will have null value
    transient public String notSerializedString = "Not serialized string";
    
    @Override
    public void setString(String value) {
	this.str = value;
    }

    @Override
    public String getString() {
	return this.str;
    }
    
    // ********
    // METHODS "writeObject" and "readObject" ARE OPRIONAL. THEY ARE USED
    // FOR "PREPARING" OBJECT FOR PRE-SERIALIZATION/POST-DESERIALIZATION
    
    // this method is called whenever object is serialized
    private void writeObject(ObjectOutputStream out) throws IOException {
	// prepare your object
	// than serialize it
	System.out.println("prepare object for serialization");
	out.defaultWriteObject(); 
    }
    
    // this method is called whenever object is deserialized
    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
	in.defaultReadObject();
	// now when object is deserialized, you can "reinitialize" all actions in it
	System.out.println("prepare object after deserialization");
    }
    
}

/** ****************************************************************************
 * INTERFACE INMPLEMENTED BY SERIALIZABLE CLASS
 * @author stanislav.zorjan
 */
interface SimpleInterface{
    public void setString(String value);
    public String getString();
}