More Examples

Text File

• A sample text file named "abc.txt".

  First line from File one
  Second Line from File one
  

• A sample text file named "xyz.txt".

  First line from File two
  Second Line from File Two
  

Display Text Files

• Display all text files inside a given directory path..

  import java.io.*;
  
  class DisplayTextFiles {
      public static void main(String[] args) throws IOException {
          String path = "C:/users/arjun/Desktop";
          File[] filesFromPath = (new File(path)).listFiles();
          for (File fileFromPath : filesFromPath) {
  
              if (fileFromPath.getName().endsWith(".txt")) { // First getName() will return the file name into string and endsWith() checks the file extension like REGEX.
                  System.out.println(fileFromPath.getName()); // Prints all txt files in Desktop.
              }
          }
      }
  }
  

Merge Text Files

• Read from "abc.txt" and "xyz.txt" and merge into "finalText.txt" file.

  import java.io.*;
  
  class MergeFiles{
      public static void main(String[] args)throws IOException{
          try{
              PrintWriter pw = new PrintWriter(new File("finalText.txt"));
              BufferedReader br = new BufferedReader(new FileReader("abc.txt"));
              String line = br.readLine();
              while (line != null ) { // Denotes no character
                  pw.write(line+"\n");
                  line = br.readLine(); // Iteratively reads the line one by one until loop terminates.
              }
  
              br = new BufferedReader(new FileReader("xyz.txt"));
              line = br.readLine();
              while (line != null) { // Denotes no character
                  pw.write(line + "\n");
                  line = br.readLine(); // Iteratively reads the line one by one until loop terminates.
              }
  
              pw.flush();
              pw.close();
              br.close();
          }catch(IOException error){
              error.printStackTrace();
          }
      }
  }
  

Merge Text Files Alternatively

• Read from "abc.txt" and "xyz.txt" and merge into "finalText.txt" file while writing each lines from both files alternatively..

  import java.io.*;
  
  class MergeFiles{
      public static void main(String[] args)throws IOException{
          try{
              PrintWriter pw = new PrintWriter(new File("finalText.txt"));
              BufferedReader brOne = new BufferedReader(new FileReader("abc.txt"));
              BufferedReader brTwo = new BufferedReader(new FileReader("xyz.txt"));
              String lineOne = brOne.readLine();
              String lineTwo = brTwo.readLine();
              while (lineOne != null || lineTwo != null) { // Denotes no character
                  pw.write(lineOne+"\n");
                  pw.write(lineTwo+"\n");
                  lineOne = brOne.readLine(); // Iteratively reads the line one by one until loop terminates.
                  lineTwo = brTwo.readLine();
              }
  
              pw.flush();
              pw.close();
              brOne.close();
              brTwo.close();
          }catch(IOException error){
              error.printStackTrace();
          }
      }
  }
  

Merge Text Files From Given Path

• Read text files from a given path and merge them.

  import java.io.*;
  class DisplayTextFiles {
      public static void main(String[] args) throws IOException {
          BufferedReader br; // Declaring a variable of BufferedReader data type so that it can be used inside loop to read every .txt files listed there.
          String path = "C:/users/arjun/Desktop/"; // This is pre-specified path, you can change it.
          PrintWriter pw = new PrintWriter(path + "mergedText.txt");
          String line; // This will get the lines on text files.
          String location;
          File[] filesFromPath = (new File(path)).listFiles();
  
          for (File fileFromPath : filesFromPath) {
              if (fileFromPath.getName().endsWith(".txt") && !fileFromPath.getName().equals("mergedText.txt")) { // First getName() will return the file name into string and endsWith() checks the file extension like REGEX. It excludes the mergedText.txt too.
                  System.out.println("Reading from " + fileFromPath.getName()); // Prints progress message in console.
                  location = path + fileFromPath.getName();
                  br = new BufferedReader(new FileReader(location));
                  pw.write("From " + fileFromPath.getName() + "\n"); // This will write the text.
                  line = br.readLine(); // Reads a line from specified file and returns string.
                  while (line != null) { // Loop executes until the line-read is not null.
                      pw.println(line + "\n"); // Writes each lines into the PrintWriter variable.
                      line = br.readLine();
                  }
                  pw.write("\n");
              }
          }
          System.out.println("Writing completed.");
          // br is not initialized at this scope, so need to close() it.
          pw.flush();
          pw.close();
      }
  }