Java.io.RandomAccessFile Class

• getFilePointer()method returns the current offset in the file. If an I/O error occurs it throws IOException.

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
 
public class RandomAccessFileClass {
 
    public static void main(String[] args) {
        try {
          RandomAccessFile raf = new RandomAccessFile("books.txt", "rw");
 
          String books[] = new String[5];
            books[0] = "Thinking In Java";
            books[1] = "Java SCJP";
            books[2] = "Java Security";
            books[3] = "Complete Reference";
            books[4] = "Real Java";
 
            for (int i = 0; i < books.length; i++) 
            {
            	System.out.println(" Writing to file :"+books[i]);
                raf.writeUTF(books[i]);
            }
            
            //positioning the File Pointer at the end of file using seek()
            raf.seek(raf.length());
            raf.writeUTF("Servlet & JSP Programming");
            System.out.println("........Writing Completed.......");

            // Move the file pointer to the beginning of the file
            raf.seek(0);
            System.out.println("=== Reading From File===");
           while (raf.getFilePointer() < raf.length())
           {
                System.out.println(raf.readUTF());
            }
        } 
        catch (FileNotFoundException e)
        {
            e.printStackTrace();
        } 
        catch (IOException e) 
        {
            e.printStackTrace();
        }
 
    }
}
              

  OUTPUT
       Writing to file :Thinking In Java
       Writing to file :Java SCJP
       Writing to file :Java Security
       Writing to file :Complete Reference
       Writing to file :Real Java
       ........Writing Completed.......
       === Reading From File===
       Thinking In Java
       Java SCJP
       Java Security
       Complete Reference
       Real Java
       Servlet & JSP Programming
              

Scanner Class

Constructors

Methods

Implementation

import java.util.Scanner;
import java.io.*;  
public class ScannerClass
{
  public static void main(String[] args)
  {
    // Declarations
    Scanner in = new Scanner(System.in);
    int rollno;
    float percentage;
   String name;
       
       // Prompts
    System.out.print("Enter your Roll no,Percentage and Name ");
    System.out.println("( Separate with a space):");   
 
    // Read in values  
    rollno = in.nextInt();
    percentage = in.nextFloat();
    name = in.nextLine();
       
    System.out.println("Here is what you entered: ");
    System.out.println("Roll no=" + rollno+" Percentage=" +percentage + " Name=" + name );
  }
 
}
              

OUTPUT
    Enter your Roll no,Percentage and Name ( Separate with a space):
    123 90.9 Rajesh Bansal
    Here is what you entered: 
    Roll no=123 Percentage=90.9 Name= Rajesh Bansal
              

ObjectInputStream & ObjectOutputStream Classes

Serialization Process

Deserialization Process

Implementation

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
class Company implements Serializable
	{
		String name,webSite;
		Company(String n,String ws)
		{
			name=n; webSite=ws;
		}
	 String getCompDetails()
		{
			return "Company Name="+name+ " Site="+webSite;	
		}
	}

class SerialzeProcess 
	{
		void serializeObject(Company p)
		{
			try{
			FileOutputStream fos=new FileOutputStream("file2.txt");
			ObjectOutputStream oos=new ObjectOutputStream(fos);
			oos.writeObject(p);
			oos.close();
			fos.close();
			System.out.println("Object Serialized Successfully.....");
			}
			catch(Exception ex){ex.printStackTrace();}
		}
	void deserializeObject()
		{
			try{
				System.out.println("------  deserializing-------");
				FileInputStream fos=new FileInputStream("file2.txt");
				ObjectInputStream oos=new ObjectInputStream(fos);
				Company pp=(Company)oos.readObject();
			System.out.println(pp.getCompDetails());
				oos.close();
				fos.close();
				System.out.println("Object deserialized Successfully.....");
				}
				catch(Exception ex){ex.printStackTrace();}
			}
	}
public class ObjectInpuOutputStreams 
{
	public static void main(String[] args) 
	{
		SerialzeProcess sp=new SerialzeProcess();
		Company pro=new Company("Dell", "www.dell.com");
		
		sp.serializeObject(pro);
		
		sp.deserializeObject();
	}
}
             

OUTPUT
Object Serialized Successfully.....
------  deserializing-------
Company Name=Dell Site=www.dell.com
Object deserialized Successfully.....