如何在 Spring Boot 中减小 PNG/JPEG 文件的大小答案

【问题标题】：How to reduce PNG/JPEG file size in spring boot如何在 Spring Boot 中减小 PNG/JPEG 文件的大小
【发布时间】：2021-12-01 15:39:52
【问题描述】：

我想在保存图像的同时减小文件大小。请将此代码作为参考。以及如何减小文件大小。

public void saveImage(MultipartFile image_one, MultipartFile image_two, MultipartFile image_three) throws Exception{
        System.out.println("Inside Save image Repo");
        
        String folder = "C:/Users/HP/Photos";
        byte[] bytes_one;
        try {
            bytes_one = image_one.getBytes();
            
            Path path1 = Paths.get(folder + image_one.getOriginalFilename()); 
            System.out.println("Path of 1st imagae : "+path1);
            
            Files.write(path1, bytes_one);
            
            System.out.println("Image-1 size : "+bytes_one.length);
        } catch (Exception e) {
            System.out.println("Inside Catch Block -> Image not found ");
            e.printStackTrace();
        }   
    }

【问题讨论】：

标签： java spring-boot spring-mvc spring-data r.java-file

【解决方案1】：

您可以使用 Java javax.imageio 库并使用函数来压缩图像字节。

这应该可以完成工作：

public byte[] compressImage(MultipartFile image) throws IOException
{

    InputStream inputStream = image.getInputStream();
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

    float imageQuality = 0.3f;

    // Create the buffered image
    BufferedImage bufferedImage = ImageIO.read(inputStream);

    // Get image writers
    Iterator<ImageWriter> imageWriters = ImageIO.getImageWritersByFormatName("jpg"); // Input your Format Name here

    if (!imageWriters.hasNext())
        throw new IllegalStateException("Writers Not Found!!");

    ImageWriter imageWriter = imageWriters.next();
    ImageOutputStream imageOutputStream = ImageIO.createImageOutputStream(outputStream);
    imageWriter.setOutput(imageOutputStream);

    ImageWriteParam imageWriteParam = imageWriter.getDefaultWriteParam();

    // Set the compress quality metrics
    imageWriteParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
    imageWriteParam.setCompressionQuality(imageQuality);

    // Compress and insert the image into the byte array.
    imageWriter.write(null, new IIOImage(bufferedImage, null, null), imageWriteParam);

    byte[] imageBytes = outputStream.toByteArray();

    // close all streams
    inputStream.close();
    outputStream.close();
    imageOutputStream.close();
    imageWriter.dispose();


    return imageBytes;
}

它返回压缩后的图像bytes，这样返回的值就可以转换成许多东西。在你的情况下，在一个文件中......

byte[] compressedImageBytes = compressImage(imageOne);

Files.write(path1, bytesOne);

【讨论】：