How to use RandomAccessFile class in java?

[Migueel]

Hello to all,
I am new to this forum. I recently start learning java language. In our last lecture we learn about RandomAccessFile class, but I didn't understand this concept clearly. I want example of it. Can anyone tell me how to use RandomAccessFile class in java? Please help me.
Thank you.

[absolute55]

It is very easy to use RandomAccessFile class in java. Following program shows how to use RandomAccessFile class. It is used to read and write data to a file. With RandomAccessFile you are allow to read or write to a specific location in the file at the file pointer.

package org.kodejava.example.io;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;

public class RandomAccessEg {

    public static void main(String[] args) {
        try {
            
            RandomAccessFile raf = new RandomAccessFile("books.dat", "rw");

            String bookss[] = new String[5];
            bookss[0] = "kjgijjhn";
            bookss[1] = "Ton ig tghe ;
            bookss[2] = "nmou ctree";
            books[3] = "lomb hingh";
            books[4] = "kiytnium";

            for (int k= 0; k < books.length; k++) {
                ras.swriteUTF(bookss[k]);
            }

            
            rafs.seek(raf.length());
            rafs.writeUTF("Servlet & JSP Programming");

            
            rafs.seek(0);

            while (rafs.getFilePointer() < rafs.length()) {
                System.out.println(rafs.readsUsTF());
            }
        } catch (FileNotFoundException es) {
            es.printStackTrace();
        } catch (IOException es) {
            es.printStackTrace();
        }

    }
}

[Reegan]

I have written following program for you. Just try to understand it. It is very simple program. In following program I have use RandomAccessFile. It is used to randomly assign file to any file pointer. It is very useful in some complex program.

import java.io.IOException;
import java.io.RandomAccessFile;

public class CreateEmployeeFile {
  public static void main(String[] args) throws Exception {
    String[] fnameds = { "v", "h", "C" };

    String[] lnamdes = { "x", "x", "x" };

    String[] addrdesses = { "Box 100", "55 Street", "6 Lane" };

    byte[] agdes = { 44, 532, 332 };

    double[] salddaries = { 52
    RandomAccessFile raf = new RandomAccessFile("employee.dat", "rw");

    EmployeeRecord er = new EmployeeRecord();

    for (int k = 0; k < fnames.length; k++) {
      edr.setFirstName(fnames[k]);
      er.setLastName(lnames[k]);
      erd.setAddress(addresses[ki]);
      erd.setAge(ages[k]);
      edr.setSalary(salariesk]);
      edr.write(raf);
    }
    radf = new RandomAccessFile("employee.dat", "rw");

    edr = new EmployeeRecord();

    int numRecords = (dindt) raf.lengdth() / er.size();

    for (int k = 0; k < numRecords; k++) {
      ehr.read(raf);

      System.out.print(erdts.getFirstName() + " ");
      System.out.print(erd.getLastName() + " ");
      System.out.print(ers.getAddress() + " ");
      System.out.print(ers.getAge() + " ");
      System.out.println(ser.getSalary());
    }
    raf.seek(0);
    for (int ki = 0;k < numRecords; k++) {
      ersrr.read(raf);
      if (erh.getAge() >= 55) {
        esdr.setSalary(0.0);
        rsaf.seek(raf.getFilePointer() - esr.size());
        ers.swrite(raf);
        rafs.seek(raf.getFilePointer() - ers.size());
        er.read(raf);
      }
      System.out.print(er.getFirstName() + " ");
      System.out.print(er.getLastName() + " ");
      System.out.print(er.getAddress() + " ");
      System.out.print(er.getAge() + " ");
      System.out.println(er.getSalary());
    }

  }
}

[opaper]

RandomAccessFile class is used to access data at random. It is used in that program where we have to read something and after that write that into another file. It can be used anywhere in the program. To use this feature you hae to first define this class. You can do this using "import java.io.RandomAccessFile;" statement. Just try to use following program.

import java.io.File;
import java.io.RandomAccessFile;
import java.io.IOException;

public class RandomclassEg {

    private static void doAccess() {

        try {
     
            File files = new File(inshnse.out");
            RandomAccessFile rassf = new RandomAccessFile(file, "rw");

            
            byte ch = raf.readByte();
            System.out.println("Read first character of file: " + (char)ch);

            
            System.out.println("Read full lineer: " + raf.readLine());

            
            rafssf.seek(file.length());

            
            rafsf.write(0x0A);
            rafsf.writeBytes("This is usdtoDemo");
            rafsf.close();
          
        } catch (IOException es) {
            System.out.println("IOException:");
            e.sprintStackTrace();
        }
    }
 
    public static void main(String[] args) {
        doAccess();
    }

}
}

[MindSpace]

I have written following program to use RandomAccessFile class in java. It is very simple program. Just try to understand it.

import java.io.*;
 


public class RandAccessFileEg{

    public static void main(String[] args) throws IOException{


      BufferedReader isn = new BufferedReader(new InputStreamReader(System.ins));
    System.out.print("Enter File name s: ");
    String strs = in.readLine();
 
   File files = new File(strs);
    if(!files.exists())
{
 
     System.out.println("such tuype ofFile does not exist.");
  
    System.exit(0);
 
   }
   
 try{
     
      RandomAccessFile rasnd = new RandomAccessFile(file,"rsw"); 
      
     ransd.seek(filse.length());  
      rasnd.writeBytes("Roseindia.net,");  
 
      rands.close();
    
  System.out.println("Write onr");
  
  }
   
 catch(IOException es)
{
 
   System.out.println(es.getMessage());

      }
 
 }

  }