使用spring-boot应用程序进行自动图像压缩/优化

Question

is there a way to automatically compress/optimize images in a spring-boot-application? As in my application the user can put any images in a folder themselves, I cannot make sure, they are compressed the best way. And as they are not uploaded through the application, I can also not create an optimized version.

So what I would like to do is to compress/optimize the images once they are requested and maybe save them in a kind of "image-cache" for a while.

Or is there a tomcat/apache-module, which already does this kind of things out-of-the box?

Thanks for your help

Answer 1

You can use javax.imageio 's classes and interface to compress a given image. Below is an example of image compression of JPG image. You can add the below main method code to your service in spring boot application.

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Iterator;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageOutputStream;

public class ImageCompression {
    public static void main(String[] args) throws FileNotFoundException, IOException{
        File imageFile = new File("YOUR_IMAGE.jpg");
        File compressedImageFile = new File("YOUR_COMPRESSED_IMAGE.jpg");

        InputStream inputStream = new FileInputStream(imageFile);
        OutputStream outputStream = new FileOutputStream(compressedImageFile);

        float imageQuality = 0.3f;

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

        //Get image writers
        Iterator<ImageWriter> imageWriters = ImageIO.getImageWritersByFormatName("jpg");

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

        ImageWriter 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);

        //Created image
        imageWriter.write(null, new IIOImage(bufferedImage, null, null), imageWriteParam);

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