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 using wget under unix. Is this possible?

Answer 1

I found the following code to work correctly. It writes bytes to the output buffer. Perhaps that methods using a writer like the System.out.println() method replaces the occurrences of \r to \n to match the target's native line ending(if not configured properly).

public class Main{
    public static void main(String[] arg) throws Exception {
        String anim= "|/-\\";
        for (int x =0 ; x < 100 ; x++) {
            String data = "\r" + anim.charAt(x % anim.length()) + " " + x;
            System.out.write(data.getBytes());
            Thread.sleep(100);
        }
    }
}

Answer 2

I have made a percentage progress bare to check the remain download file.

I call the method periodically in my file download to check the total file-size and remaining and present that in %.

It can be used for other task purpose as well.

Test and output example

progressPercentage(0, 1000);
[----------] 0%

progressPercentage(10, 100);
[*---------] 10%

progressPercentage(500000, 1000000);
[*****-----] 50%

progressPercentage(90, 100);
[*********-] 90%

progressPercentage(1000, 1000);
[**********] 100%

Test with for loop

for (int i = 0; i <= 200; i = i + 20) {
    progressPercentage(i, 200);
    try {
        Thread.sleep(500);
    } catch (Exception e) {
    }
}

The method can be easily modified:

public static void progressPercentage(int remain, int total) {
    if (remain > total) {
        throw new IllegalArgumentException();
    }
    int maxBareSize = 10; // 10unit for 100%
    int remainProcent = ((100 * remain) / total) / maxBareSize;
    char defaultChar = '-';
    String icon = "*";
    String bare = new String(new char[maxBareSize]).replace('\0', defaultChar) + "]";
    StringBuilder bareDone = new StringBuilder();
    bareDone.append("[");
    for (int i = 0; i < remainProcent; i++) {
        bareDone.append(icon);
    }
    String bareRemain = bare.substring(remainProcent, bare.length());
    System.out.print("\r" + bareDone + bareRemain + " " + remainProcent * 10 + "%");
    if (remain == total) {
        System.out.print("\n");
    }
}

Answer 3

This would be possible with a Java Curses library. This is what I have found. I haven't used it myself and I don't know if it is cross-platform.

Answer 4

public class Main {

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

        System.out.println("Loading : ");
            int count =1;
            for(int j=1;j<150;j++){

                System.out.print("\r");
                if(count==1){
                    System.out.print("/");
                    count++;
                }
                else if(count==2){
                    System.out.print("|");
                    count++;
                }
                else if(count==3){
                    System.out.print("-");
                    count++;
                }
                else if(count==4){
                    System.out.print("\\");
                    count++;
                }
                else if(count==5){
                    System.out.print("|");
                    count++;
                }
                else
                    count = 1;
            Thread.sleep(200);
        }

        }

    }

Answer 5

I have implemented this sort of thing before. Its not so much about java, but what characters to send to the console.

The key is the difference between \n and \r. \n goes to the start of a new line. But \r is just carriage return - it goes back to the start of the same line.

So the thing to do is to print your progress bar, for example, by printing the string

"|========        |\r"

On the next tick of the progress bar, overwrite the same line with a longer bar. (because we are using \r, we stay on the same line) For example:

"|=========       |\r"

What you have to remember to do, is when done, if you then just print

"done!\n"

You may still have some garbage from the progress bar on the line. So after you are done with the progress bar, be sure to print enough whitespace to remove it from the line. Such as:

"done             |\n"

Hope that helps.

Answer 6

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");
}