java 将jpg格式图片提出成txt文件 。

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.*;

public class ImageConvertTool {
    private static String imagePath, txtPath;
    private static int imageHeight, imageWidth;
    private static String replaceString = 
    "$@B%8&WM#*oahkbmZO0QJUYXzcvunxrjft/|()1{}[]?-_+~<>i!lI;:,^`'. ";
    private static StringBuffer imageString = new StringBuffer();

    public ImageConvertTool(String imagePath, String txtPath) {
        this.imagePath = imagePath;
        this.txtPath = txtPath;
        imageProcess();
        imageSave();
    }

    private static void imageProcess() {
        try {
            BufferedImage image = ImageIO.read(new File(imagePath));
            imageHeight = image.getHeight();
            imageWidth = image.getWidth();
            for (int height = 0; height < imageHeight; height += 2) {
                for (int width = 0; width < imageWidth; width++) {
                    // 像素点RBG值获取
                    int pixel = image.getRGB(width, height);
                    int R = (pixel & 0xff0000) >> 16;
                    int B = pixel & 0xff;
                    int G = (pixel & 0xff00) >> 8;

                    // 灰度计算公式
                    float pixelGray = 0.299f * R + 0.587f * G + 0.114f * B;
                    int pixelIndex = Math.round(pixelGray * (replaceString.length() + 1) / 255);

                    // 将灰度值转成字符
                    String pixelChar = pixelIndex >= replaceString.length() ? " "
                            : String.valueOf(replaceString.charAt(pixelIndex));

                    // 控制台上输出
                    System.out.print(pixelChar);

                    // 添加到imageString中
                    imageString.append(pixelChar);
                }
                System.out.println();
                imageString.append('\n');
            }
        } catch (IOException error) {
            error.printStackTrace();
        }
    }

    private static void imageSave() {
        File file = new File(txtPath);
        if (!file.exists())
            try {
                file.createNewFile();
            } catch (Exception error) {
                error.printStackTrace();
            }
        try {
            FileWriter fileWriter = new FileWriter(file);
            String temp = new String(imageString);
            fileWriter.write(temp);
            fileWriter.close();
        } catch (Exception error) {
            error.printStackTrace();
        }
    }
}

public class Main {
    public static void main(String []args){
        // 输入保存的txt文件路径
        String txtPath = "cat.txt";
        // 输入准备转换的图片路径
        String imagePath = "cat.jpg";
        new ImageConvertTool(imagePath,txtPath);
    }
}