In this article, I will show you how to read JPEG images in Java using ImageIO and JDeli. We also have a related article covering how to write JPG files in Java.
ImageIO is able to handle most JPEG files but does not fully implement the spec. If you want more complete JPEG support, JDeli has been built up to provide this.
What is JPEG?
JPEG (Joint Photographic Experts Group) is a very well supported file format and works with all modern web browsers. It does not include an opacity channel so there is no transparency.
JPEG works best for colour images. It is commonly used for digital camera images as it gives you high-quality images. One main feature of JPEG is that it enables you to choose between quality and file size; you can sacrifice quality for a smaller file or vice versa.
The file name extension for JPEG files are: .jpg or .jpeg
How to read a JPEG image in Java with ImageIO
Step 1 Create a File, InputStream or URL Object pointing to the JPEG.
Step 2 Pass the value into ImageIO which will convert to a BufferedImage.
BufferedImage image = ImageIO.read(jpegFileOrInputStreamOrURL)How to read a JPEG image in Java with JDeli
Step 1 Add JDeli to your class or module path (download the trial jar).
Step 2 Create a File handle, InputStream pointing to the raw JPEG image. You can also use a byte[] containing the image data.
Step 3 Read the JPEG image into a BufferedImage
BufferedImage image = JDeli.read(jpegFileOrInputStreamOrByte); Start reading and writing images with one line of code
Read: BufferedImage image = JDeli.read(streamOrFile);
Write: JDeli.write(myBufferedImage, OutputFormat.HEIC, outputStreamOrFile)
