Introduction: Serialization is the process of converting an object
into a stream of bytes in order to store the object or transmit it to memory, a
database, or a file.The reverse process of creating object
from binary stream is called deserialization. A Java object is serializable if its class or any of
its superclasses implements either the java.io.Serializable
interface or its subinterface, java.io.Externalizable.
Serialization classes:
OutputStream : we’ll use FileOutputStream
to write data to a file.
ObjectOutputStream : writes primitive data types and graphs of Java
objects to an OutputStream.
WriteObject() Method : it writes an
object to the stream.
InputStream : We’ll use FileInputStream
as source stream.
ObjectInputStream: It reads from inputStream.
ReadObject()
Method:
It reads raw bytes and convert to an
object.
In
this sample I’ll use a person class and an address class. The person class
holds the reference of an address class. We will serialize the data and store
it in c:\ project\ folder as tst.ser file. To deserialize the data we will
create an instance of FileInputStream class that takes this tst.ser file as
source.
Code:
import
java.io.Serializable;
public class person
implements Serializable {
String fname;
String lname;
int age;
address addr; //reference class
public
person()
{}
public
person(String fn,String ln,int age,address a)
{
this.fname=fn;
this.lname=ln;
this.age=age;
this.addr=a;
}
public
String getFName() {return fname;}
public
String getLName() {return lname;}
public int getAge() {return age;}
public
address getAddress() { return addr;}
public
String setFName(String fn) { return fname=fn;}
public
String setLName(String ln) { return lname=ln;}
public int setAge(int a) { return age=a;}
public
address setAddress(address adr){return addr=adr;}
}
import
java.io.Serializable;
public class address
implements Serializable{
String str;
String city;
String state;
String zip;
public
address(){};
public
address(String a,String c,String s,String z)
{
super();
this.str=a;this.city=c;this.state=s;this.zip=z;
}
public
String getStreet(){return str;}
public
String getCity() {return city;}
public
String getState() {return state;}
public
String getZip(){return zip;}
public
String setStr(String st){return str=st;}
public
String setCity(String ct){return city=ct;}
public
String setSttae(String st){return state=st;}
public
String setZip(String zp){return zip=zp;}
}
import
java.io.*;
public class
serializeDeserailize {
public static void
main(String[] args)
{
//create a person instance
person
p=new person();
p.setFName("Adam");
p.setLName("Smith");
p.setAge(20);
//create an address instance
address
a=new address();
a.setStr("Lake Shore Drive");
a.setCity("Chicago");
a.setSttae("IL");
a.setZip("65987");
p.setAddress(a);
//Serialize person object
try {
FileOutputStream
fos=new FileOutputStream("c:/project/tst.ser");
ObjectOutputStream obj=new
ObjectOutputStream (fos);
obj.writeObject(p);
obj.close();
fos.close();
}catch (Exception e)
{
e.printStackTrace();
}
// Deserialize
p=null;
try {
InputStream
fin=new FileInputStream("c:/project/tst.ser");
ObjectInputStream
in=new ObjectInputStream(fin);
p=(person)
in.readObject(); //cast to person object
in.close();
fin.close();
}catch
(Exception ex)
{
ex.printStackTrace();
}
System.out.println("After Deserialization:" );
System.out.println("First Name:" + p.getFName());
System.out.println("Last Name:" + p.getLName());
System.out.println(("Age:" +
p.getAge()));
System.out.println("Address:" +
p.getAddress().getStreet() + " " + p.getAddress().getCity()
+ "," +
p.getAddress().getState() + "-" +
p.getAddress().getZip());
}
}
Output:
First Name:Adam
Last Name:Smith
Age:20
Address:Lake
Shore Drive Chicago,IL-65987
