how to check if a file is an png image file,using java

Question

I am building an automate png to jpg, everything is built, but I have a problem detecting png files. Now I am using the file name: I am checking if the end of the file matches .png but this is not working for png files that do not end with .png.

Any ideas?

Answer 1

u can try this

import javax.activation.MimetypesFileTypeMap;
import java.io.File;

class GetMimeType {
  public static void main(String args[]) {
    File f = new File(filePath);
    System.out.println("Mime Type of " + f.getName() + " is " +
                         new MimetypesFileTypeMap().getContentType(f));

}

or

try

public String getContentType(File file) throws IOException {
        return Files.probeContentType(file.getAbsolutePath());
}

Answer 2

You can check the header of the file.
See http://en.wikipedia.org/wiki/Portable_Network_Graphics#File_header.