控制台进度显示就地更新：Update Progress in place

Posted 2022-05-11 javartisan

控制台显示进度信息：

import java.util.Collections;
import java.util.List;
import java.util.StringJoiner;
import java.util.concurrent.TimeUnit;

/**
 * Created on 2022-04-25
 */
public class InPlacePrint 

    public static void main(String[] args) 
        long total = 235;
        long startTime = System.currentTimeMillis();

        for (int i = 1; i <= 100; i++) 
            try 
                Thread.sleep(200);
                //                // printProgress(startTime, total, i);
                //                System.out.print("\\b\\b" + i + "\\\\b 退格(BS) ，将当前位置移到前一列");
                //                //System.out.print("\\r " + i); //  回车(CR) ，将当前位置移到本行开头


                List<String> eqs = Collections.nCopies(i, "=");
                List<String> blanks = Collections.nCopies(100 - i, "#");
                String join = String.join("", eqs);
                String blank = String.join("", blanks);
                String progress = new StringBuilder()
                        .append("\\r")
                        .append("[")
                        .append(join)
                        .append(blank)
                        .append("]")
                        .append("  ")
                        .append(i)
                        .append("%")
                        .toString();
                System.out.print(progress);
             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')  // 重点之处: \\r回到行首
                .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((int) (Math.log10(total)) - (int) (Math.log10(current)), " ")))
                .append(String.format(" %d/%d, ETA: %s", current, total, etaHms));

        System.out.print(string);