Input a formated text file in a TextArea

Question

I have a well formated text file which looks like this:

Human  10000
Alien  2000
Dog    40000

How can I insert this text in an JTextArea without destroying the format?

I tried with the same format I used for the file but it doesn't work:

String formatStr = "%-15s %-15s";
while((currentLine = br.readLine()) != null) {
    area.setText(area.getText() + "\n" + c++ + ".");
    area.setText(String.format(formatStr, area.getText(), String.valueOf(currentLine)));
}

Answer 1

You would call JTextArea's append(...) method, not the setText(...), if you want to append multiple lines in your loop, would set the Font as Font.MONOSPACED, and probably would use String.format(...) which is much more reliable and flexible than tabs. But myself, I'd use a JTable to display tabular data.

I mean something like...

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

import javax.swing.*;
import javax.swing.table.DefaultTableModel;

public class TabularData extends JPanel {
   private static final String FILE_NAME = "dataFile.txt"; // **** this is wrong ****
   private static final String[] COLUMN_NAMES = {"Species", "Count"};
   private static final String REGEX = "\\s+";
   private MyModel myModel = new MyModel();
   private JTable table = new JTable(myModel);

   public TabularData() {
      add(new JScrollPane(table));

      File dataFile = new File(FILE_NAME);
      try(BufferedReader br = new BufferedReader(new FileReader(dataFile))) {
         String currentLine = "";
         while ((currentLine = br.readLine()) != null) {
            String[] tokens = currentLine.split(REGEX);
            if (tokens.length == 2) {
               String species = tokens[0].trim();
               int count = Integer.parseInt(tokens[1].trim());
               myModel.addRow(new Object[]{species, count});
            }
         }
      } catch (FileNotFoundException e) {
         e.printStackTrace();
      } catch (IOException e) {
         e.printStackTrace();
      } catch (NumberFormatException e) {
         e.printStackTrace();
      }
   }

   private class MyModel extends DefaultTableModel {

      public MyModel() {
         super(COLUMN_NAMES, 0);
      }

      @Override
      public Class<?> getColumnClass(int columnIndex) {
         if (getRowCount() > 0) {
            Object cell = getValueAt(0, columnIndex);
            if (cell != null) {
               return cell.getClass();
            }
         }
         return super.getColumnClass(columnIndex);
      }
   }

   private static void createAndShowGui() {
      JFrame frame = new JFrame("TabularData");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(new TabularData());
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}