使用Java代码编写去图片水印功能

要去除图片水印，可以使用Java的图像处理库ImageIO和BufferedImage。

首先，需要读取图片文件，可以使用以下代码：

File inputFile = new File("input.jpg");
BufferedImage inputImage = ImageIO.read(inputFile);

接下来，需要获取图片的宽度和高度，并创建一个新的BufferedImage来存储修改后的图像：

int width = inputImage.getWidth();
int height = inputImage.getHeight();
BufferedImage outputImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

然后，可以使用Graphics2D来将原始图像绘制到新的图像上：

Graphics2D graphics = outputImage.createGraphics();
graphics.drawImage(inputImage, 0, 0, null);
graphics.dispose();

现在，可以使用Java的像素操作来去除水印。例如，可以使用以下代码将颜色值为白色的像素替换为周围像素的平均颜色值：

for (int x = 0; x < width; x++) {
    for (int y = 0; y < height; y++) {
        int color = outputImage.getRGB(x, y);
        int red = (color & 0xff0000) >> 16;
        int green = (color & 0xff00) >> 8;
        int blue = color & 0xff;
        if (red > 240 && green > 240 && blue > 240) {
            int newColor = getAverageColor(outputImage, x, y);
            outputImage.setRGB(x, y, newColor);
        }
    }
}

其中，getAverageColor()方法用于计算给定像素周围像素的平均颜色值：

private static int getAverageColor(BufferedImage image, int x, int y) {
    int red = 0;
    int green = 0;
    int blue = 0;
    int count = 0;
    for (int i = x - 1; i <= x + 1; i++) {
        for (int j = y - 1; j <= y + 1; j++) {
            if (i >= 0 && i < image.getWidth() && j >= 0 && j < image.getHeight()) {
                int color = image.getRGB(i, j);
                red += (color & 0xff0000) >> 16;
                green += (color & 0xff00) >> 8;
                blue += color & 0xff;
                count++;
            }
        }
    }
    red /= count;
    green /= count;
    blue /= count;
    return (red << 16) | (green << 8) | blue;
}

最后，可以将修改后的图像保存到文件中：

File outputFile = new File("output.jpg");
ImageIO.write(outputImage, "jpg", outputFile);

完整的示例代码如下：

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;

public class WatermarkRemoval {
    public static void main(String[] args) throws Exception {
        File inputFile = new File("input.jpg");
        BufferedImage inputImage = ImageIO.read(inputFile);
        int width = inputImage.getWidth();
        int height = inputImage.getHeight();
        BufferedImage outputImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D graphics = outputImage.createGraphics();
        graphics.drawImage(inputImage, 0, 0, null);
        graphics.dispose();
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                int color = outputImage.getRGB(x, y);
                int red = (color & 0xff0000) >> 16;
                int green = (color & 0xff00) >> 8;
                int blue = color & 0xff;
                if (red > 240 && green > 240 && blue > 240) {
                    int newColor = getAverageColor(outputImage, x, y);
                    outputImage.setRGB(x, y, newColor);
                }
            }
        }
        File outputFile = new File("output.jpg");
        ImageIO.write(outputImage, "jpg", outputFile);
    }

    private static int getAverageColor(BufferedImage image, int x, int y) {
        int red = 0;
        int green = 0;
        int blue = 0;
        int count = 0;
        for (int i = x - 1; i <= x + 1; i++) {
            for (int j = y - 1; j <= y + 1; j++) {
                if (i >= 0 && i < image.getWidth() && j >= 0 && j < image.getHeight()) {
                    int color = image.getRGB(i, j);
                    red += (color & 0xff0000) >> 16;
                    green += (color & 0xff00) >> 8;
                    blue += color & 0xff;
                    count++;
                }
            }
        }
        red /= count;
        green /= count;
        blue /= count;
        return (red << 16) | (green << 8) | blue;
    }
}