Command line progress bar in Java

Question

I have a Java program running in command line mode. I would like to display a progress bar, showing the percentage of job done. The same kind of progress bar you would see u

Answer 1

public static void main(String[] argv) throws Exception{


    System.out.write("\r".getBytes());
    int percentage =10;
    while(percentage <= 100) {
        String temp =generateStars(percentage);
        System.out.write(temp.getBytes());
        System.out.print("\b\b\b");
        percentage = percentage+10;
        Thread.sleep(500);
    }
}

    public static String generateStars(int percentage)
    {
        int startsNum = percentage / 4;
        StringBuilder builder = new StringBuilder();
        while(startsNum >= 0)
        {
        builder.append("*");
        startsNum--;
        }
        builder.append(percentage+"%");
        return builder.toString();
    }

Answer 2

Here is a modified version of the above:

private static boolean loading = true;
private static synchronized void loading(String msg) throws IOException, InterruptedException {
    System.out.println(msg);
    Thread th = new Thread() {
        @Override
        public void run() {
            try {
                System.out.write("\r|".getBytes());
                while(loading) {
                    System.out.write("-".getBytes());
                    Thread.sleep(500);
                }
                System.out.write("| Done \r\n".getBytes());
            } catch (IOException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    };
    th.start();
}

... and in main:

loading("Calculating ...");

Answer 3

I use a "bouncing" progress bar when I need to delay a tool to prevent a race condition.

private void delay(long milliseconds) {
    String bar = "[--------------------]";
    String icon = "%";

    long startTime = new Date().getTime();
    boolean bouncePositive = true;
    int barPosition = 0;

    while((new Date().getTime() - startTime) < milliseconds) {
        if(barPosition < bar.length() && barPosition > 0) {
            String b1 = bar.substring(0, barPosition);
            String b2 = bar.substring(barPosition);
            System.out.print("\r Delaying: " + b1 + icon + b2);
            if(bouncePositive) barPosition++;
            else barPosition--;
        } if(barPosition == bar.length()) {
            barPosition--;
            bouncePositive = false;
        } if(barPosition == 0) {
            barPosition++;
            bouncePositive = true;
        }

        try { Thread.sleep(100); }
        catch (Exception e) {}
    }
    System.out.print("\n");
}