Cómo reducir el tamaño del archivo de imagen en java

Question

Quiero reducir el tamaño del archivo de imagen de una imagen cargada antes de guardarla en el servidor (para reducir el tiempo de carga). ¿Cómo puedo hacerlo usando Java?

Answer 1

Este tipo de pregunta ha sido respondida bastantes veces en este sitio. Le sugiero que consulte How to resize the original image into a common size of image in Java? o busque el tamaño de imagen de java en este sitio.

Answer 2

/* 
* This will get an image file and returns a byte array resized by the given value. 
*/ 
package tajneed; 

import java.awt.image.BufferedImage; 
import java.io.ByteArrayOutputStream; 
import java.io.File; 
import javax.imageio.ImageIO; 
import org.imgscalr.Scalr; 

public class ImageResizer { 

    public static byte[] resize(File icon) { 
     try { 
      BufferedImage originalImage = ImageIO.read(icon); 

      originalImage= Scalr.resize(originalImage, Scalr.Method.QUALITY, Scalr.Mode.FIT_EXACT, 128, 153); 
      //To save with original ratio uncomment next line and comment the above. 
      //originalImage= Scalr.resize(originalImage, 153, 128); 
      ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
      ImageIO.write(originalImage, "jpg", baos); 
      baos.flush(); 
      byte[] imageInByte = baos.toByteArray(); 
      baos.close(); 
      return imageInByte; 
     } catch (Exception e) { 
      return null; 
     } 


    } 
} 

Answer 3

Que este código sea útil le ayudará a cambiar el tamaño y la calidad de las imágenes.

protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException { 
     boolean isMultipart = ServletFileUpload.isMultipartContent(request); 
      if (!isMultipart) { 
      } else { 
       FileItemFactory factory = new DiskFileItemFactory(); 
       ServletFileUpload upload = new ServletFileUpload(factory); 
       List items = null; 
       try { 
        items = upload.parseRequest(request); 
       } catch (FileUploadException e) { 
        System.out.println("Unable to load image" + e.getMessage());} 
       Iterator itr = items.iterator(); 
       while(itr.hasNext()) { 
        System.out.println(items.size()); 
         FileItem item = (FileItem) itr.next(); 
         if (!item.isFormField()) { 
          try { 
           int size = 200;// size of the new image. 
           //take the file as inputstream. 
           InputStream imageStream = item.getInputStream(); 
           //read the image as a BufferedImage. 
           BufferedImage image = javax.imageio.ImageIO.read(imageStream); 
           //cal the sacleImage method. 
           BufferedImage newImage = scaleImage(image, size); 
           String path = getServletContext().getRealPath("/image"); 
           //write file. 
           File file = new File(path, "testimage.jpg"); 
           ImageIO.write(newImage, "JPG", file); 
          } catch (Exception e) { 
           System.out.println("Unable to save the image" + e.getMessage()); 
           //System.out.println(path); 
        }//if 
       }//iter 
     } 
    private BufferedImage scaleImage(BufferedImage bufferedImage, int size) { 
     double boundSize = size; 
      int origWidth = bufferedImage.getWidth(); 
      int origHeight = bufferedImage.getHeight(); 
      double scale; 
      if (origHeight > origWidth) 
       scale = boundSize/origHeight; 
      else 
       scale = boundSize/origWidth; 
      //* Don't scale up small images. 
      if (scale > 1.0) 
       return (bufferedImage); 
      int scaledWidth = (int) (scale * origWidth); 
      int scaledHeight = (int) (scale * origHeight); 
      Image scaledImage = bufferedImage.getScaledInstance(scaledWidth, scaledHeight, Image.SCALE_SMOOTH); 
      // new ImageIcon(image); // load image 
      // scaledWidth = scaledImage.getWidth(null); 
      // scaledHeight = scaledImage.getHeight(null); 
      BufferedImage scaledBI = new BufferedImage(scaledWidth, scaledHeight, BufferedImage.TYPE_INT_RGB); 
      Graphics2D g = scaledBI.createGraphics(); 
       g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR); 
      g.drawImage(scaledImage, 0, 0, null); 
      g.dispose(); 
      return (scaledBI); 
    }