Question

using java File Details – Build a class called FileDetails.java. When you instantiate this class and give it a filename, it will report back the size of the file, whether the file is Readable and whether the file is Writeable; plus any other file information that you might deem important. This cd goes in main FileDetails fd=newFileDetails(“anyfile.doc”); All other code goes in the constructor. Write a String to a File using PrintStream – This time build a class WriteString. This class, when instantiated, will write a string to a file by using a PrintStream object connected to a FileOutputStream Object. This cd goes in main WriteString ws = new WriteString(“f1.txt”,“Hello world”); All other code goes in the constructor. Write Integers to a File – This time build a class WriteInts. This class, when instantiated, will create a new file and write an array of integers to this new file. All the code to write the data to the file goes in the Constructor. This code goes in main int myArr[] = {16, 31, 90, 45, 89}; WriteInts wi = new WriteInts(“mydata.dat”, myArr); All other code goes in the constructor. Read Integers from a File – This time build a class ReadInts. This class, when instantiated, will read the integers from the file given, and print them to the Console. All the code to write the data to the file goes in the Constructor. This code goes in main ReadInts ri = new ReadInts(“mydata.dat”); All other code goes in the constructor.

Answer 1

// import required package file
import java.io.File;

// The Filedetails class
public class FileDetails {
  
   // Constructor that performs the action
   public FileDetails(String filename)
   {
       // File object to get details
       File file=new File(filename);
       // printing obsolute path
       System.out.println("Absolute path of file:"+file.getAbsolutePath());
       // printing file size in bytes
       System.out.println("File Size in bytes:"+file.length());
       // Checking if file is readable
       if(file.canRead())
       System.out.println("The file is readable");
       else
          
           System.out.println("The file is not readable");
       // checking if file is writable
       if(file.canWrite())
           System.out.println("The file is writable");
       else
           System.out.println("The file is not writable");
   }
  
// main method goes here
   public static void main(String[] args) {
       // TODO Auto-generated method stub
       // object instantiation
       FileDetails fd=new FileDetails("anyfile.doc"); // You should give exact path and file name here
  

   }

}

// Importing required packages
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;

// the writestring class
public class WriteString {
  
   // Writestring class
   public WriteString(String filename,String text) throws FileNotFoundException
   {
       // File object
       File file=new File(filename);
       // Printsteam class that connects file using file output stream
       PrintStream ps=new PrintStream(new FileOutputStream(file));
       // using println method to write to the file
       ps.println(text);
      
   }
   // main method to execute the code
   public static void main(String[] args) throws FileNotFoundException
   {
       // the writestring class instantiation
       WriteString ws=new WriteString("f1.txt","Hello World");  // You should give exact path and file name here
   }

}

// importing packages
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;

// The writints class
public class WriteInts {
  
   // the constructor to instantiate
   public WriteInts(String filename,int[] myArr) throws FileNotFoundException
   {
       // File object
       File file=new File(filename);
       // Using print stream to write integers
       PrintStream ps=new PrintStream(new FileOutputStream(file));
       //Looping through array elements to write every element
       for(int i=0;i<myArr.length;i++)
           ps.print(myArr[i]+" ");
   }
   // main goes here

   public static void main(String[] args) throws FileNotFoundException {
       // TODO Auto-generated method stub
       // Required lines in the main
       int myArr[] = {16, 31, 90, 45, 89};
       WriteInts wi = new WriteInts("mydata.dat", myArr);   // You should give exact path and file name here

   }

}

// import required packages
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

// The readints class
public class ReadInts {
  
   // the constructor
   public ReadInts(String filename) throws IOException
   {
       // file object
       File file=new File(filename);

       // This time we are using buffered reader to read from the file
       BufferedReader br=new BufferedReader(new FileReader(file));
       // line to store the entire line from the file
       String line;
       // String array to store ints in the form of strings
       String[] sarr=null;
       // Buffered reader to read lines
       while((line=br.readLine())!=null)
       {
           // Splitting line using space
           // Remeber we have used a space to seperate number
           // while writing to file in the othe class
          
           sarr=line.split(" ");
       }
       // Creating a new array
       int[] myArr=new int[sarr.length];
       // Using for loop to store ints in form string to integers
       for(int i=0;i<sarr.length;i++)
       {
           // Using parseint method to convert string to int
           myArr[i]=Integer.parseInt(sarr[i]);
       }
      
   }

   public static void main(String[] args) throws IOException {
       // TODO Auto-generated method stub
       ReadInts ri = new ReadInts("mydata.dat");  // You should give exact path and file name here

   }

}