【工具类】——图片缩放

在java中对于图片的处理一般都是使用Graphics2D类来实现。
Graphics2D 是 Java 2D API 的核心类，用于在 Java 平台上渲染二维形状、文本和图像。它是 Graphics 类的扩展，提供了更复杂的图形操作功能，包括几何变换、颜色管理、文本布局等。
用来实现图片的指定尺寸缩放
工具类代码
public class ImageResizer {

public static byte[] imageResizer(byte[] imageBytes, int width, int height) {try {ByteArrayInputStream bais = new ByteArrayInputStream(imageBytes);BufferedImage originalImage = ImageIO.read(bais);// 创建缩放后的图像BufferedImage resizedImage = new BufferedImage(width, height, originalImage.getType());Graphics2D graphics = resizedImage.createGraphics();// 改善图像质量graphics.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);// 设置透明度，保持原始图像的透明度graphics.setComposite(AlphaComposite.Src);// 绘制图像graphics.drawImage(originalImage, 0, 0, width, height, null);graphics.dispose();ByteArrayOutputStream baos = new ByteArrayOutputStream();ImageIO.write(resizedImage, "png", baos);return baos.toByteArray();} catch (Exception e) {return null;}
}

}

测试类

public static void main(String[] args) {// 指定原始图像文件路径和目标尺寸String inputImagePath = "/Users/qweasdzxc/Downloads/test0.jpeg"; // 替换为实际路径int targetWidth = 100; // 目标宽度int targetHeight = 100; // 目标高度// 读取原始图像文件try {File inputFile = new File(inputImagePath);BufferedImage originalImage = ImageIO.read(inputFile);// 将原始图像转换为字节数组ByteArrayOutputStream baos = new ByteArrayOutputStream();ImageIO.write(originalImage, "png", baos);byte[] imageBytes = baos.toByteArray();// 调整图像大小byte[] resizedImageBytes = imageResizer(imageBytes, targetWidth, targetHeight);// 将调整大小后的图像保存到新文件if (resizedImageBytes != null) {ByteArrayInputStream bais = new ByteArrayInputStream(resizedImageBytes);BufferedImage resizedImage = ImageIO.read(bais);ImageIO.write(resizedImage, "png", new File("/Users/qweasdzxc/Downloads/test1.jpeg")); // 替换为实际路径System.out.println("Image resized successfully.");} else {System.out.println("Failed to resize image.");}} catch (IOException e) {e.printStackTrace();}
}