Java图像合并：解决ImageIO.write保存JPG文件失败的常见陷阱

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

public class ImageMerger {
    public static void main(String[] args) throws IOException {
        String imagePathPrefix = "../../Desktop/temp/"; // 请替换为实际图片路径

        // 1. 加载源图像
        BufferedImage leftImage = ImageIO.read(new File(imagePathPrefix + "006.jpg"));
        BufferedImage rightImage = ImageIO.read(new File(imagePathPrefix + "007.jpg"));

        if (leftImage == null || rightImage == null) {
            System.err.println("无法读取源图像，请检查路径是否正确或图像文件是否存在。");
            return;
        }

        // 2. 计算合并后图像的宽度和高度
        int mergedWidth = leftImage.getWidth() + rightImage.getWidth();
        int mergedHeight = Math.max(leftImage.getHeight(), rightImage.getHeight()); // 取较高的高度

        // 3. 创建一个新的BufferedImage来存放合并后的图像
        // 注意：此处使用了BufferedImage.TYPE_INT_ARGB，这是导致JPG保存失败的关键点
        BufferedImage mergedImage = new BufferedImage(mergedWidth, mergedHeight, BufferedImage.TYPE_INT_ARGB);

        // 4. 获取Graphics2D对象，用于绘制
        Graphics2D g2d = mergedImage.createGraphics();

        // 5. 将左侧图像绘制到新图像的左侧
        g2d.drawImage(leftImage, 0, 0, null);
        // 将右侧图像绘制到新图像的右侧，其X坐标为左侧图像的宽度
        g2d.drawImage(rightImage, leftImage.getWidth(), 0, null);

        // 6. 释放Graphics2D资源
        g2d.dispose();

        // 尝试保存合并后的图像，此时可能会遇到ImageIO.write返回false的问题
        // boolean success = ImageIO.write(mergedImage, "jpg", new File(imagePathPrefix + "merged_output.jpg"));
        // System.out.println("图像保存成功: " + success); // 可能会输出 false
    }
}

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

public class ImageMergerFixed {
    public static void main(String[] args) throws IOException {
        String imagePathPrefix = "../../Desktop/temp/"; // 请替换为实际图片路径

        BufferedImage leftImage = ImageIO.read(new File(imagePathPrefix + "006.jpg"));
        BufferedImage rightImage = ImageIO.read(new File(imagePathPrefix + "007.jpg"));

        if (leftImage == null || rightImage == null) {
            System.err.println("无法读取源图像，请检查路径是否正确或图像文件是否存在。");
            return;
        }

        int mergedWidth = leftImage.getWidth() + rightImage.getWidth();
        int mergedHeight = Math.max(leftImage.getHeight(), rightImage.getHeight());

        // 关键修正：使用BufferedImage.TYPE_INT_RGB，因为JPG不支持透明度
        BufferedImage mergedImage = new BufferedImage(mergedWidth, mergedHeight, BufferedImage.TYPE_INT_RGB);

        Graphics2D g2d = mergedImage.createGraphics();
        g2d.drawImage(leftImage, 0, 0, null);
        g2d.drawImage(rightImage, leftImage.getWidth(), 0, null);
        g2d.dispose(); // 释放Graphics2D资源

        // 保存合并后的图像
        boolean success = ImageIO.write(mergedImage, "jpg", new File(imagePathPrefix + "001.jpg"));
        System.out.println("图像保存成功: " + success); // 现在应该返回 true
    }
}