Java program to merge two or more files alternatively into third file

Assume we have three files as −

output1.txt

Hello how are you

output2.txt

Welcome to Tutorialspoint

output3.txt

We provide simply easy learning

Example

Following Java example merges the contents of the above three files alternatively into a single file −

import java.util.Scanner;
public class MergingFiles {
   public static void main(String args[]) throws IOException {
      Scanner sc1 = new Scanner(new File("D://input1.txt"));
      Scanner sc2 = new Scanner(new File("D://input2.txt"));
      Scanner sc3 = new Scanner(new File("D://input3.txt"));
      FileWriter writer = new FileWriter("D://result.txt");
      String str[] = new String[3];
      while (sc1.hasNextLine()||sc2.hasNextLine()||sc3.hasNextLine()) {
         str[0] = sc1.nextLine();
         str[1] = sc2.nextLine();
         str[2] = sc3.nextLine();
      }
      writer.append(str[0]+"\n");
      writer.append(str[1]+"\n");
      writer.append(str[2]+"\n");
      writer.flush();
      System.out.println("Contents added ");
   }
}

Output

Contents added

If the above three files are in the same directly you can rewrite the sample program as −

Example

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
public class MergingFiles {
   public static void main(String args[]) throws IOException {
      //Creating a File object for directory
      File directoryPath = new File("D:\\example");
      //List of all files and directories
      File filesList[] = directoryPath.listFiles();
      Scanner sc = null;
      FileWriter writer = new FileWriter("D://output.txt");
      for(File file : filesList) {
         sc = new Scanner(file);
         String input;
         StringBuffer sb = new StringBuffer();
         while (sc.hasNextLine()) {
            input = sc.nextLine();
            writer.append(input+"\n");
         }
         writer.flush();
      }
      System.out.println("Contents added ");
   }
}

Output

Contents added