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Creating a text file filled with random integers in Java

Silly question, maybe. But I'm trying to fill a blank text file with 512 integers, each on every new line. I was able to randomize and write them to a file, but they create a huge bunch of numbers, which is what I wanted. Can anyone help me fix my code?

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.*;

public class Randomizer {

      public static void main() {
        // The target file
        File out = new File("random.txt");
        FileWriter fw = null;
        int n = 512;
        // Try block: Most stream operations may throw IO exception
        try {
            // Create file writer object
            fw = new FileWriter(out);
            // Wrap the writer with buffered streams
            BufferedWriter writer = new BufferedWriter(fw);
            int line;
            Random random = new Random();
            while (n > 0) {
                // Randomize an integer and write it to the output file
                line = random.nextInt(1000);
                writer.write(line + "\n");
                n--;
            }
            // Close the stream
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(0);
        }
    }
}

The content of random.txt at the end of the run: 9463765593113665333437829621346187993554694651813319223268147794541131427390, etc.

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3 answers


You seem to be using line endings on Windows, different on Unix / Windows / Classic Mac.



Try \ r \ n for Windows based systems, or try opening a .txt file in Wordpad instead of Notepad. \ N is commonly used on Unix systems, and the Notepad app included with Windows has been known to not handle them well.

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            writer.write(line + "\n");

Don't use this.

You use BufferedWriter

and a BufferedWriter

has .newLine()

.



So replace with:

writer.write(line);
writer.newLine();
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Check this line from the javadoc for BufferedWriter

:

Method A is provided newLine()

, which uses the platform's own line separator concept as defined by the line.separator system property. Not all platforms use the newline character ( '\n'

) for line termination. Therefore, calling this method to terminate each output line is preferable to write the newline character directly.

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