17.4

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

import javax.swing.*;

public class Test_17_4 extends JFrame{
private JLabel jl1 = new JLabel("Filename");
private JTextField jt1 = new JTextField("d:\\a.txt",10);
private JButton jb1 = new JButton("View");
private JPanel jholdPanel = new JPanel();
private JP jp1 = new JP();
private String s;

public Test_17_4(){
add(jp1);
}

public static void main(String[] args) {
// TODO Auto-generated method stub
Test_17_4 frame = new Test_17_4();
frame.setTitle("Test_17_4");
frame.setSize(400,500);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}

class JP extends JPanel{
private JTextArea jt = new JTextArea();
private File file;
private Scanner input;

public JP(){
//set textarea
jt.setLineWrap(true);
jt.setWrapStyleWord(false);
jt.setEditable(false);

JScrollPane scro = new JScrollPane(jt);

//create jscrollpanel to hole the textarea
JScrollPane scrollPane = new JScrollPane(jt);

jholdPanel.setLayout(new FlowLayout(FlowLayout.LEFT));
jholdPanel.add(jl1);
jholdPanel.add(jt1);
jholdPanel.add(jb1);

jb1.addActionListener(new ActionListener(){

@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
s = jt1.getText();
try {
jp1.setText(s);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

});

setLayout(new BorderLayout(5,5));
add(scrollPane,BorderLayout.CENTER);
add(jholdPanel,BorderLayout.SOUTH);
}

public void setText(String s) throws FileNotFoundException{
file = new File(s);
if(file.canRead() && file.exists()) {
input = new Scanner(file);
while(input.hasNext()) {
jt.append(input.nextLine());
jt.append("\n");
}
}
else System.out.println("does not exists!");
input.close();
}
}

}