Data output stream not working

Question

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

public class two extends JFrame implements ActionListener
{


JLabel l1,l2;
    JTextArea a1,a2;
    JButton b1;
    JMenuBar bar;
    JMenu menu;
    JMenuItem m1,m2;
    JPanel p;
    ArrayList<String> a;
    DataOutputStream d1;

//gui part of the programme

public void go()
{
    p=new JPanel();
    bar=new JMenuBar();
    menu=new JMenu("File");
    m1=new JMenuItem("Save");
    m1.addActionListener(this);
    m2=new JMenuItem("New");
    menu.add(m1);
    menu.add(m2);


Font f=new Font("Arial",Font.BOLD,16);
l1=new JLabel("Question ");
l1.setAlignmentX(CENTER_ALIGNMENT);
l1.setFont(f);
l2=new JLabel("Answer");
l2.setFont(f);
l2.setAlignmentX(RIGHT_ALIGNMENT);
a1=new JTextArea(10,50);
JScrollPane a4 = new JScrollPane(a1);
a4.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
a4.setMaximumSize(new Dimension(600,220));
a4.setAlignmentX(CENTER_ALIGNMENT);
a2=new JTextArea(10,50);
JScrollPane a3 = new JScrollPane(a2);
a3.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
a3.setMaximumSize(new Dimension(600,220));
a3.setAlignmentX(CENTER_ALIGNMENT);
b1=new JButton("Next Card");
b1.setAlignmentX(LEFT_ALIGNMENT);
b1.addActionListener(this);

bar.add(menu);
setJMenuBar(bar);
BoxLayout g=new BoxLayout(p,BoxLayout.Y_AXIS);
p.setLayout(g);
p.add(l1);
p.add(Box.createRigidArea(new Dimension(15,15)));
p.add(a4);
p.add(Box.createRigidArea(new Dimension(15,15)));
p.add(l2);
p.add(Box.createRigidArea(new Dimension(15,15)));
p.add(a3);
p.add(Box.createRigidArea(new Dimension(25,25)));
p.add(b1);
getContentPane().add(p);
setVisible(true);
setSize(500,600);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    }

public static void main(String[] args) {
    two obj=new two();
    obj.go();
}


public void actionPerformed(ActionEvent e)
{
 a=new ArrayList<String>();

//part where the text area content is saved to a listarray

 if(e.getSource()==b1)
{
String l=new String(a1.getText()+"/");
String w=new String (a2.getText()+"\n");
a.add(l);
a.add(w);

//values are added to arraylist as shown by the value of a.size()

System.out.println(a.size());
a1.setText("");
a2.setText("");

}

//method to save listarray to a file using filechooser

if(e.getSource()==m1){

JFileChooser fileSave = new JFileChooser();
int retrival=fileSave.showSaveDialog(this);
File d=fileSave.getSelectedFile();

if (retrival == JFileChooser.APPROVE_OPTION) {

        try{
        System.out.println(d);

//this part is not being called

        d1=new DataOutputStream(new FileOutputStream(d+".txt");

        for(String o:a)
        {
        d1.writeChars(o);
     System.out.println("\nIS SUCCESFULLY WRITTEN INTO FILE!");
    }
        d1.close();


    }catch(Exception ex){System.out.println(ex);}
}
}

}
}

You don't close your resources safely; you should create both outputs separately and close them in a finally block; or just use a `FileWriter` since you seem to be writing text. Or even better, use Guava, use a `Closer`. — fge, Jul 09 '13 at 09:23
Please speak up the problem and post only the problematic section,not full page code. — Naveen, Jul 09 '13 at 09:27
the file is created but nothing is written into it even if i use FileWriter — GAURAV KHERA, Jul 09 '13 at 09:48
This question appears to be off-topic because it is too localised — user207421, Jul 09 '13 at 09:59

Reimeus · Accepted Answer · 2013-07-09T12:00:02.950

1

DataOutputStream is working as expected.

Nothing is written to file as a new ArrayList is created which replaces the previous instance a when actionPerformed is invoked.

a = new ArrayList<String>();

clearing the contents of any previous data so nothing is written to file. Move this statement to the constructor so that the ArrayList is only initialized once. Use clear to clear the List.

Aside: JTextArea has access to the write method which allows its content to be written directly to file

edited Jul 09 '13 at 12:00

answered Jul 09 '13 at 09:32

Reimeus

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Thank you moving ArrayList to a constructor solved my problem... – GAURAV KHERA Jul 09 '13 at 09:52

Data output stream not working

1 Answers1