Question

JAVA City Files Program:

Deserialize objects from a file. Print the data contained in the fields of the objects to a plaintext file.

The Cities.dat binary file contains TEN serialized City objects. Each City object has name, population, latitude, and longitude fields. Prior to being serialized into the file, all ten objects had their fields set.

City Java:

public class City implements Serializable {

    private String name;
    private int population;
    private double latitude;
    private double longitude;

    public City(String n, int p, double lat, double lon) {
        name = n;
        population = p;
        latitude = lat;
        longitude = lon;
    }

    public String getName() {
        return name;
    }

    public double getLatitude() {
        return latitude;
    }

    public double getLongitude() {
        return longitude;
    }

    public int getPopulation() {
        return population;
    }

}

Program will need to first deserialize all ten City objects. You can use ten separate variables or put them in an array.

Program will need to produce a plaintext file where each line of the text file contains the city’s name, population, latitude, and longitude. Your program will need to use the “getter” methods of the deserialized City objects to retrieve the values of the four fields. The text file your program produces should have 10 lines; Each field should be separated by one space.

For example, if the first City object had its fields set to:

• (name) Newark

• (population) 277140

• (latitude) 40.735657

• (longitude) -74.172363

then the first line in the output text file should read:

Newark 277140 40.735657 -74.172363

Answer 1

Output.txt
Seattle 608660 47.606209 -122.332069
Las Vegas 583756 36.169941 -115.139832
Philadelphia 1580863 39.952583 -75.165222
New York 8175133 40.712776 -74.005974
Tampa 335709 27.950575 -82.457176
Austin 790390 30.267153 -97.743057
Denver 600158 39.739235 -104.99025
Minneapolis 382578 44.977753 -93.265015
Los Angeles 3792621 34.052235 -118.243683
Cleveland 396698 41.499321 -81.694359


output.txt screenshot


Code:

import java.io.BufferedWriter;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.ArrayList;
import java.util.List;

import Assignment.City;

public class CitySerializerDeserializer {

   //File to be created and read from
   private static final File file = new File("Cities.dat");

   public static void main(String[] args) {

       try {

           //de-serialize call
           List<City> deserializedCities = fetchCities();

           if(writeCitiesIntoFileAsPlainText(new File("output.txt"), deserializedCities)) {
              
               System.out.println("Cities written in plain text to output file");
           }

       } catch (Exception e) {
           e.printStackTrace();
       }

   } //end of main
  
   /*
   * De-serializes objects from file
   */
   public static List<City> fetchCities() throws ClassNotFoundException, IOException {

       List<City> cities = new ArrayList<>();
      
       City city = null;

       //try with resources which will automatically close the connections
       try (
               FileInputStream fis = new FileInputStream(file); //file reader
               ObjectInputStream oos = new ObjectInputStream(fis); // this reads objects from file
           ) {
          
           try {
           //reads the objects from file
               while ((city = (City) oos.readObject()) != null) {
                   cities.add(city);
               }
           } catch (EOFException e) {
               //end of file reached don't do anything
           }
       }

       //return the result read from file
       return cities;

   }
  
   /*
   * Writes the cities into file in below format
   * cityName population latitude longitude
   */
   public static boolean writeCitiesIntoFileAsPlainText(File file, List<City> cities) throws FileNotFoundException, IOException {
      
       //try with resources which will automatically close the connections
       try (
               FileWriter fos = new FileWriter(file);
               BufferedWriter bw = new BufferedWriter(fos) //writes in file
           ) {
          
           //take each city and write in file
           for(City city : cities) {
              
               //city written
               bw.write(
                           city.getName() +
                           " " +
                           city.getPopulation()
                           + " " + city.getLatitude()
                           + " " + city.getLongitude()
                           +"\n"
                       );
           }
       }
      
       //All went well then return true
       return true;
   }
}