Creating a simple data output file in Java

Question

I am trying to write a simple data output file. When I execute the code I get a "No file exist" as the output and no data.txt file is created in the dir.

What am I missing? The odd thing is that it was working fine the other night, but when I loaded it up today to test it out again, this happened.

Here is the code:

import java.io.*;
import java.util.*;

public class DataStreams {

    public static void main(String[] args) throws IOException {

        try {

            DataOutputStream out = new DataOutputStream(new FileOutputStream("C:\\data.txt"));
            for (int i = 0; i < 10; i++) {
                out.write(i);
            }
        } catch (IOException ioe) {
            System.out.println("No file exist");
        }
    }
}

The data file should be a simple display of numbers 1 through 9.

Thanks for your input.

Well, after deleting and reentering the directory address of where I wanted to write the file to - it worked. I didn't answer my question yet in case anyone has anything to add as to why it might not have worked initially. I apologize for not troubleshooting this idea before posting question. — TroutmasterJ, Apr 06 '14 at 19:09
try printing the exception which is being thrown by using ioe.printStackTrace() in the catch block. Then you can confirm what is the exception. — bgth, Apr 06 '14 at 19:10

score 0 · Answer 1 · answered Apr 06 '14 at 19:05

0

Create a text file named data.txt in c: .You must have deleted the file. Creating that file manually will work

answered Apr 06 '14 at 19:05

Junaid Shirwani

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Reimeus · Accepted Answer · 2014-04-06T19:19:28.600

0

On Windows platforms, C:\ is a restricted path by default. Previously the application may have been run as administrator allowing access.

Solution: Use a different location

DataOutputStream out = 
    new DataOutputStream(new FileOutputStream("C:/temp/data.txt"));

edited Apr 06 '14 at 19:19

answered Apr 06 '14 at 19:07

Reimeus

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score 0 · Answer 3 · answered Apr 06 '14 at 19:08

0

You should have a look at the exception itself:

System.out.println("No file exist");
System.out.println(ex.getMessage());

Perhaps you have not the necessary rights, to access C:\ with your program.

answered Apr 06 '14 at 19:08

Thomas Junk

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score 0 · Answer 4 · answered Apr 06 '14 at 19:14

To write data into a file, you should first create it, or, check if it exists.Otherwise, an IOException will be raised.

Writing in C:\ is denied by default, so in your case even if you created the file you will get an IOException with an Access denied message.

public static void main(String[] args) throws IOException {
    File output = new File("data.txt");
    if(!output.exists()) output.createNewFile();
    try {
        DataOutputStream out = new DataOutputStream(new FileOutputStream(output));
        for (int i = 0; i < 10; i++) {
            out.write(i);
        }
    } catch (IOException ioe) {
        System.out.println("No file exist");
    }
}

Creating a simple data output file in Java

4 Answers4