CODEWITHSUNDEEP
javafileclasscompare
Joseph Arlen Wolfrum
Joseph Arlen Wolfrum

Reputation: 1

need a method to read two files and out put the difference using a scanner class

This is what I have so far. I'm not sure where to go from here. I need a method to output the difference in two files

    package JwolfrumCh6;
    import java.util.*;
    import java.io.*;
    import java.util.Scanner;

    public class JwolfrumCh6 {

        public static void main(String[] args) throws FileNotFoundException  
    {
            Scanner console = new Scanner(System.in);

            System.out.print("Enter File one Name");
            String file1 = console.nextLine();
            Scanner input1 = new Scanner(new File(file1));

            System.out.print("Enter File two Name");
            String file2 = console.nextLine();
            Scanner input2 = new Scanner(new File(file2));
        }
        public static void compareFiles(Scanner input1, Scanner input2) {

            while(input1.hasNextLine() || input2.hasNextLine()) {

            }

        }
    }

Upvotes: 0

Views: 593

Answers (1)

Ganesh S
Ganesh S

Reputation: 520

Call the static method in main and implement below logic in your compareFiles method.

  1. Read all lines of file 1 to an ArrayList
  2. Read all lines of file 2 to another ArrayList

  3. Use removeAll method of ArrayList as shown below to get the differences in each of these files.

    import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class FML {

public static void main(String[] args) throws FileNotFoundException {
    Scanner console = new Scanner(System.in);

    System.out.print("Enter File one Name");
    String file1 = console.nextLine();
    Scanner input1 = new Scanner(new File(file1));

    System.out.print("Enter File two Name");
    String file2 = console.nextLine();
    Scanner input2 = new Scanner(new File(file2));
    compareFiles(input1, input2);
}

public static void compareFiles(Scanner input1, Scanner input2) {
     List<String> list1 = new ArrayList<String>();
     List<String> list2 = new ArrayList<String>();
    while (input1.hasNextLine()) {
        list1.add(input1.nextLine());
    }
    while (input2.hasNext()) {
        list2.add(input2.nextLine());
    }
    List<String> tmpList = new ArrayList<String>(list1);
    tmpList.removeAll(list2);

    System.out.println("content from file1 which is different from file2");
    for(int i=0;i<tmpList.size();i++){
        System.out.println(tmpList.get(i)); 
    }

    System.out.println("content from file2 which is different from file2");

    tmpList = list2;
    tmpList.removeAll(list1);
    for(int i=0;i<tmpList.size();i++){
        System.out.println(tmpList.get(i)); 
    }

}
}

Upvotes: 1

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