使用Swing在JPanel中创建JTextArea

Question

I want to create a Jtextarea in the first half of the below panel under tab2. I want to iterate and write the contents present in the test.txt file into this newly created Jtext area. The text.txt file is present in the location (C:\\test.txt) . Can someone suggest me how to achieve this for the below code. (Note: The below code is a JPane with three tabs tab1,tab2,tab3) and the tab 2 has been splited into two halves.)

I am new to the Jtextarea concept so it will be nice from understanding viewpoint if anyone can provide some suggestion code for my below code:

text.txt contents in my local disk is as below

username:test1  
Password:test1  
DataBasename: testDB

CODE:

import javax.swing.*;
import java.awt.*;

public class SplitPaneExp {

    public static void main(String[] args){
        Runnable r = new Runnable() {
            public void run() {
                JFrame frame = new JFrame("WELCOME");
                // A better close operation..
                frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                JTabbedPane tab = new JTabbedPane();
                frame.add(tab, BorderLayout.CENTER);
                JButton button = new JButton("1");
                tab.add("tab1", button);

                // this GridLayout will create a single row of components,
                // with equal space for each component
                JPanel tab2Panel = new JPanel(new GridLayout(0,1));
                button = new JButton("2");
                tab2Panel.add(button);
                tab2Panel.add(new JButton("Second window"));
                // add the panel containing two buttons to the tab
                tab.add("tab2", tab2Panel);

                button = new JButton("3");
                tab.add("tab3", button);
                // a better sizing method..
                //frame.setSize(400,400);
                frame.pack();
                frame.setVisible(true);
            }
        };
        SwingUtilities.invokeLater(r);
    }
}

Answer 1

import javax.swing.*;
import java.awt.*;
import java.io.*;

public class SplitPaneExp {

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            public void run() {
                JFrame frame = new JFrame("WELCOME");
                // A better close operation..
                frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                JTabbedPane tab = new JTabbedPane();
                frame.add(tab, BorderLayout.CENTER);
                JButton button = new JButton("1");
                tab.add("tab1", button);

                // this GridLayout will create a single row of components,
                // with equal space for each component
                JPanel tab2Panel = new JPanel(new GridLayout(0, 1));
//                button = new JButton("2");

                //Hi, I added a few things here!
                String output = "";
                try {
                    BufferedReader br = new BufferedReader(new FileReader(new File("C:\test.txt")));
                    String line = br.readLine();
                    while(line != null) {
                        if(output.length() > 0) {
                            output = output + "\n";
                        }
                        output = output + line;
                        line = br.readLine();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }

                JTextArea jta = new JTextArea(output);
                tab2Panel.add(jta);
                // Done.

//                tab2Panel.add(button);
                tab2Panel.add(new JButton("Second window"));
                // add the panel containing two buttons to the tab
                tab.add("tab2", tab2Panel);

                button = new JButton("3");
                tab.add("tab3", button);
                // a better sizing method..
                //frame.setSize(400,400);
                frame.pack();
                frame.setVisible(true);
            }
        };
        SwingUtilities.invokeLater(r);
    }
}

Hope it helps.