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:
- Serialization in javaJava
- Serialization interview questions and answers
- serialversionuid in java serialization
- externalizable in java
- Transient keyword in java
- Difference between Serializable and Externalizable in Java
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
Create Employee.java same as last example in src->org.arpit.java2blog
1.Employee.java
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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; } } |
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Create DeserializeMain.java in src->org.arpit.java2blog
2.DeserializeMain.java
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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:
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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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