Java图片压缩三种高效压缩方案详细解析

java public static void extracted2() { '
String path = "C:\test.jpg"; 
String savePath = "D:\compressed.jpg"; 
int maxWidth = 800; 
int maxHeight = 600; 
compressImage(new File(path), new File(savePath), maxWidth, maxHeight); 
}
compressImage 写法为kotlin语法法，需要自己转换
fun compressImage(inputFile: File, outputFile: File, maxWidth: Int, maxHeight: Int) {
        try {
            val image = ImageIO.read(inputFile)
            val originalWidth = image.width
            val originalHeight = image.height
            var newWidth = originalWidth
            var newHeight = originalHeight

            // 计算新的宽度和高度，保持比例
            if (originalWidth > maxWidth || originalHeight > maxHeight) {
                val ratio = Math.min(maxWidth.toDouble() / originalWidth, maxHeight.toDouble() / originalHeight)
                newWidth = (originalWidth * ratio).toInt()
                newHeight = (originalHeight * ratio).toInt()
            }

            val resizedImage = BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB)
            resizedImage.createGraphics().apply {
                drawImage(image.getScaledInstance(newWidth, newHeight, java.awt.Image.SCALE_SMOOTH), 0, 0, null)
                dispose()
            }

            // 确保输出目录存在
            val outputPath: Path = Paths.get(outputFile.parent)
            if (!Files.exists(outputPath)) {
                Files.createDirectories(outputPath)
            }

            ImageIO.write(resizedImage, "jpg", outputFile)
        } catch (e: IOException) {
            e.printStackTrace()
        }
    }

java public static void extracted4() { 
	for (int i = 1; i <=10; i++) { 
		float quality = 0.1f * i; 
		compressImage(inputFile, outputFile, quality); 
	} 
}
public static void compressImage(File inputFile, File outputFile, float quality) throws IOException {
        // 读取图片
        BufferedImage image = ImageIO.read(inputFile);

        // 获取图片写入器
        Iterator<ImageWriter> writers = ImageIO.getImageWritersByFormatName("webp");
        ImageWriter writer = writers.next();

        // 设置写入器的输出目标
        ImageOutputStream ios = ImageIO.createImageOutputStream(outputFile);
        writer.setOutput(ios);

        // 创建图片写入器配置
        IIOImage imageIO = new IIOImage(image, null, null);
        ImageWriteParam param = writer.getDefaultWriteParam();

        // 设置压缩质量
        if (param.canWriteCompressed()) {
            param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
            param.setCompressionQuality(quality);
        }

        // 写入图片
        writer.write(null, imageIO, param);

        // 关闭资源
        ios.close();
        writer.dispose();
    }

public static void extracted6() {
        String path = "C:\\Users\\美众\\Pictures\\test2.jpg";
        for (int i = 1; i <=10; i++) {
            float quality = 0.0f + i * 0.1f;
            System.out.println("quality:" + quality);
            String savePath = "D:\\save\\test2-webp-"+quality+".jpg";
            File inputFile = new File(path); // 原始图片文件
            File outputFile = new File(savePath);
            try {
                jpg2webp(inputFile, outputFile,quality);
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }
public static void jpg2webp(File oldfile, File newfile,float quality){
        try {
            // 获取原始文件的编码
            BufferedImage image = ImageIO.read(oldfile);
            // 创建WebP ImageWriter实例
            ImageWriter writer = ImageIO.getImageWritersByMIMEType("image/webp").next();
            // 配置编码参数
            WebPWriteParam writeParam = new WebPWriteParam(writer.getLocale());
            // 设置压缩模式
            writeParam.setCompressionMode(WebPWriteParam.MODE_EXPLICIT);
            System.out.println("getCompressionTypes:"+JSON.toJSON(writeParam.getCompressionTypes()));
//            "Lossy"-有损,"Lossless"-无损
            writeParam.setCompressionType(writeParam.getCompressionTypes()[0]);
            writeParam.setCompressionQuality(quality);
            // 配置ImageWriter输出
            writer.setOutput(new FileImageOutputStream(newfile));
            // 进行编码，重新生成新图片
            writer.write(null, new IIOImage(image, null, null), writeParam);
            System.out.println("jpg文件转成webp格式成功");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }