Question

This assignment involves 2 Java programs 1) Write a Java program to read a CSV (Comma separated values) text file. The text file will contain comma separated values in each line. Each line contains data in this format: String(20), String(5),String(10), double. There will be multiple lines with each line containing the same number of values. Ask the user to enter the path for the CSV file for reading the file. After reading the data from the file output the data to the console (one line at a time) with the data in each line in properly aligned columns. Then write the data to a serialized file called "assignment2.ser" to the local project folder .

2) In the second program, read the serialized file and output the data in columns to the console (one line at a time) with the data in each line in properly aligned columns.

Answer 1

Note: Create "input.csv" file in D drive with following demo data

String11,String12,String13,Double1
String21,String22,String23,Double2
String31,String32,String33,Double3
String41,String42,String43,Double4
String51,String52,String53,Double5

Code:

import java.util.Arrays;
import java.io.*;
public class SerializedFile implements Serializable
{
String line;
String data[][] = new String[100][4];
int count = 0;

void readFromFile()
    {
    try
      {
      // BufferedReader object to read data from file
      BufferedReader read = new BufferedReader(new FileReader("d:\\input.csv"));

      while ((line = read.readLine()) != null) //read data line by line
         {
         data[count] = line.split(","); //split into array of strings
         count++; //line counter
         }
      read.close(); //close input file
      }
    catch(FileNotFoundException e) //exception for file not found
      {
      System.out.println("File not found.");
      }
    catch(Exception ex) //other exceptions like permission denied
      {
      System.out.println(ex.toString());
      }
    }

void printData()   //to print data
    {
    for(int i=0; i<count; i++)
      {
      System.out.println(Arrays.toString(data[i])); //print data
      //you may also print one by one. eg data[i][0], data[i][1]....
      }
    }

public static void main(String arga[]) //main method to control the program
    {
    SerializedFile obj = new SerializedFile(); //crating object of class. it will call constructor
    obj.readFromFile();

    System.out.println("\nReading Data from File\n");
    obj.printData();

    String filename = "assignment2.ser";

    // Serialization is a process to convert objects into a writable byte stream.
    //Once converted into a byte-stream, these objects can be written to a file.
    try
           {
            //Saving of object in a file
            FileOutputStream file = new FileOutputStream(filename);
            ObjectOutputStream out = new ObjectOutputStream(file);

            // Method for serialization of object
            out.writeObject(obj);

            out.close();
            file.close();

            System.out.println("\nObject has been serialized\n");
            }
        catch(IOException ex)
            {
            System.out.println("IOException is caught");
            }

    SerializedFile newObj = null;

    System.out.println("\nReading Data from Deserialized object\n");
    obj.printData();
    // Deserialization is process of reading back
    try
            {
            // Reading the object from a file
            FileInputStream file = new FileInputStream(filename);
            ObjectInputStream in = new ObjectInputStream(file);

            // Method for deserialization of object
            newObj = (SerializedFile)in.readObject();

            in.close();
            file.close();
            }

        catch(IOException ex)
            {
            System.out.println("IOException is caught");
            }

        catch(ClassNotFoundException ex)
            {
            System.out.println("ClassNotFoundException is caught");
            }
    }
}

Output:

     

Code Screenshot: