File length and Byte[] size doesn't match in JAVA-CodePudding

I am trying to convert a image to byte[] which will be sent to a service, will determine the file size if it is allowable or not. But I am getting different size in of actual image file and byte[]. My test code:

File file=new File("path/photo.jpg"); //around 4.5 MB
img = ImageIO.read(file);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ImageIO.write(img, "jpg", bos );
byte [] data = bos.toByteArray();
System.out.println("fileSize:" file.length());
System.out.println("byteSize:"  data.length);

output

 fileSize:4544732 //equals to actual image size
 byteSize:1468863

My target is: I need to measure the actual filesize from the byte[] of that image.

CodePudding user response：

ImageIO is not needed for your use-case.

Try this instead.

final byte[] content = Files.readAllBytes(file.toPath());