How to read object from a file in java

In this post, we will see how to read object from file in java. In last post, we have already seen how to write object to a file and created employee.ser , now in this post, we are going to read same file and retrieve back Employee object.

Java Serialization Tutorial:

Steos for reading object from file are:

Reading object from file using ObjectInputStream may be referred as Deserialization.

Lets take an example:
Create Employee.java same as last example in src->org.arpit.java2blog

1.Employee.java

package org.arpit.java2blog;

import java.io.Serializable;

public class Employee implements Serializable{

private static final long serialVersionUID = 1L;

int employeeId;

String employeeName;

String department;

public int getEmployeeId() {

return employeeId;

}

public void setEmployeeId(int employeeId) {

this.employeeId = employeeId;

}

public String getEmployeeName() {

return employeeName;

}

public void setEmployeeName(String employeeName) {

this.employeeName = employeeName;

}

public String getDepartment() {

return department;

}

public void setDepartment(String department) {

this.department = department;

}

Create DeserializeMain.java in src->org.arpit.java2blog

2.DeserializeMain.java

package org.arpit.java2blog;

import java.io.IOException;

import java.io.ObjectInputStream;

public class DeserializeMain {

/**

* @author Arpit Mandliya

public static void main(String[] args) {

Employee emp = null;

try

{

FileInputStream fileIn =new FileInputStream("employee.ser");

ObjectInputStream in = new ObjectInputStream(fileIn);

emp = (Employee) in.readObject();

in.close();

fileIn.close();

}catch(IOException i)

{

i.printStackTrace();

return;

}catch(ClassNotFoundException c)

{

System.out.println("Employee class not found");

c.printStackTrace();

return;

}

System.out.println("Deserialized Employee...");

System.out.println("Emp id: " + emp.getEmployeeId());

System.out.println("Name: " + emp.getEmployeeName());

System.out.println("Department: " + emp.getDepartment());

}

3.Run it:

When you run above DeserializeMain.java and you will get following output:

Deserialized Employee...

Emp id: 101

Name: Arpit

Department: CS

These are some simple steps to read object from file. If you want to go through some complex scenario you can go through Serialization in java

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