What is the best approach to define a specific file type in Java?

Question

What is the best approach to define a specific file type in Java?

I am trying to use the following approach to identify specific file types using Java. I need to implement things like this in my web application.

package filetype;

import java.io.File;
import java.net.URLConnection;

final public class FileType
{
    public static void main(String[] args)
    {
        File temp=new File("G:/mountain.jpg");
        System.out.println(URLConnection.guessContentTypeFromName(temp.getAbsolutePath()));

        temp=new File("G:/myFile.txt");
        System.out.println(URLConnection.guessContentTypeFromName(temp.getAbsolutePath()));

        temp=new File("G:/zipByJava.zip");
        System.out.println(URLConnection.guessContentTypeFromName(temp.getAbsolutePath()));

        temp=new File("G:/MLM/Login.aspx");
        System.out.println(URLConnection.guessContentTypeFromName(temp.getAbsolutePath()));

        temp=new File("G:/power_point.pptx");
        System.out.println(URLConnection.guessContentTypeFromName(temp.getAbsolutePath()));

        temp=new File("G:/excel_sheet.xlsx");
        System.out.println(URLConnection.guessContentTypeFromName(temp.getAbsolutePath()));

        temp=new File("G:/word_document.docx");
        System.out.println(URLConnection.guessContentTypeFromName(temp.getAbsolutePath()));
    }
}

It displays the following output to the console.

image/jpeg
text/plain
application/zip
null
null
null
null

In the last four cases, it displays null

and cannot recognize the file type of this file. What is the best approach for detecting a specific file type in Java?

+3

java file-type

Bhavesh 12 Mar 12 at 15:34

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1 answer

Java42 · Answer 1 · 2012-03-12T16:30:33+0000

Use

Files.probeContentType()

http://openjdk.java.net/projects/nio/javadoc/java/nio/file/Files.html#probeContentType(java.nio.file.Path)

And add custom detectors for any odd ball types you think you will come across.

Edit:

Here is the JavaDoc oracle for v7

http://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#probeContentType(java.nio.file.Path)

What is the best approach to define a specific file type in Java?

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