Java ImageIO.write（）最多需要6秒

Question

I am writing an web application where I need to send an image from servlet to client. Image is generated dynamically and is quite big(+-2MB). It might be jpeg, png, or gif.

Now, I am using ImageIO.write() to write the image to output stream, but its veeeery slow. It takes up to 6 seconds till the client see the image. I need to speed it up.

Any suggestions?

btw. I am aware of Looking for a faster alternative to ImageIO topic. But it didn't help me. Since it's slow with PNG ImageMagick is not a solution and I have tested JAI and it was even worse.

Thanks in advance

Edit:

To show you some code:

BufferedImage bi = [code to generate Image];
response.setContentType(mime);
ServletOutputStream out = response.getOutputStream();
ImageIO.write(bi,"png",out);

I stripped down Exception handling for readability.

Answer 1

Image encoding in java is pretty slow in general but you may also want to ensure you have the native libraries installed as they make quite a noticeable difference in performance.

http://download.java.net/media/jai-imageio/builds/release/1.1/INSTALL-jai_imageio.html

Answer 2

Be aware that ImageIO by default uses temporary files as cache when creating ImageInputStreams and ImageOutputStreams . This can be switched off by calling ImageIO.setUseCache(false) .

For a more detailed explanation see this answer .

Answer 3

Are you sure that the

ImageIO

takes so long - maybe there is another problem, eg

• slow (network) connection to the client
• the generation (calculation) of the image takes a lot of time