Java程式合併目錄中所有檔案的內容

import java.io.*;
public class Demo{
   public static void main(String[] args) throws IOException{
      File my_dir = new File("path to place where file is generated");
      PrintWriter my_writer = new PrintWriter("The .txt where changes are stored");
      String[] file_names = my_dir.list();
      for (String file_names : fileNames){
         System.out.println("Content read from " + file_names);
         File my_file = new File(my_dir, file_names);
         BufferedReader my_reader = new BufferedReader(new FileReader(my_file));
         my_writer.println("The file contains " + file_names);
         String my_line = my_reader.readLine();
         while (my_line != null){
            my_writer.println(my_line);
            my_line = my_reader.readLine();
         }
         my_writer.flush();
      }
      System.out.println("All data from files have been read and " + my_dir.getName() + "merged");
   }
}

All file contents will be merged into a single text file.