Is there are easy way to implement a rolling percentage for a process in Java, to be displayed in the console? I have a percentage data type (double) I generated during a particular process, but can I force it to the console window and have it refresh, instead of just printing a new line for each new update to the percentage? I was thinking about pushing a cls and updating, because I'm working in a Windows environment, but I was hoping Java had some sort of built-in capability. All suggestions welcomed! Thanks!
You can print a carriage return \r
to put the cursor back to the beginning of line.
Example:
public class ProgressDemo {
static void updateProgress(double progressPercentage) {
final int width = 50; // progress bar width in chars
System.out.print("\r[");
int i = 0;
for (; i <= (int)(progressPercentage*width); i++) {
System.out.print(".");
}
for (; i < width; i++) {
System.out.print(" ");
}
System.out.print("]");
}
public static void main(String[] args) {
try {
for (double progressPercentage = 0.0; progressPercentage < 1.0; progressPercentage += 0.01) {
updateProgress(progressPercentage);
Thread.sleep(20);
}
} catch (InterruptedException e) {}
}
}
I use following code:
public static void main(String[] args) {
long total = 235;
long startTime = System.currentTimeMillis();
for (int i = 1; i <= total; i = i + 3) {
try {
Thread.sleep(50);
printProgress(startTime, total, i);
} catch (InterruptedException e) {
}
}
}
private static void printProgress(long startTime, long total, long current) {
long eta = current == 0 ? 0 :
(total - current) * (System.currentTimeMillis() - startTime) / current;
String etaHms = current == 0 ? "N/A" :
String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(eta),
TimeUnit.MILLISECONDS.toMinutes(eta) % TimeUnit.HOURS.toMinutes(1),
TimeUnit.MILLISECONDS.toSeconds(eta) % TimeUnit.MINUTES.toSeconds(1));
StringBuilder string = new StringBuilder(140);
int percent = (int) (current * 100 / total);
string
.append('\r')
.append(String.join("", Collections.nCopies(percent == 0 ? 2 : 2 - (int) (Math.log10(percent)), " ")))
.append(String.format(" %d%% [", percent))
.append(String.join("", Collections.nCopies(percent, "=")))
.append('>')
.append(String.join("", Collections.nCopies(100 - percent, " ")))
.append(']')
.append(String.join("", Collections.nCopies(current == 0 ? (int) (Math.log10(total)) : (int) (Math.log10(total)) - (int) (Math.log10(current)), " ")))
.append(String.format(" %d/%d, ETA: %s", current, total, etaHms));
System.out.print(string);
}
The result:
I have written such a package in Java.
https://github.com/ctongfei/progressbar
I don't think there's a built-in capability to do what you're looking for.
There is a library that will do it (JLine).
See this tutorial
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