Java Digest File digestFile(File file)

Description

digest File

License

Open Source License

Declaration

public static byte[] digestFile(File file) throws IOException 

Method Source Code

//package com.java2s;
/*//from w  w w  .  j ava2s.co m
Copyright 2015 Rudolf Fiala
    
This file is part of Alpheus AFP Parser.
    
Alpheus AFP Parser is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
Alpheus AFP Parser is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with Alpheus AFP Parser.  If not, see <http://www.gnu.org/licenses/>
*/

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Main {
    public static byte[] digestFile(File file) throws IOException {
        byte[] buffer = new byte[10 * 1024];

        MessageDigest md;
        try {
            md = MessageDigest.getInstance("MD5");

            InputStream is = null;
            DigestInputStream dis = null;
            try {
                is = new FileInputStream(file);
                dis = new DigestInputStream(is, md);
                while (dis.read(buffer) > -1)
                    ;
            } finally {
                try {
                    if (dis != null)
                        dis.close();
                    else if (is != null)
                        is.close();
                } catch (IOException e) {
                }
            }
            byte[] digest = md.digest();
            return digest;
        } catch (NoSuchAlgorithmException e1) {
            return null;
        }
    }
}

Related

1. digestFile(File file, String algorithm)
2. digestFile(String filename, String algorithm)