Java MD5 File computeMD5(File file)

Description

Computes the MD5 checksum of the given File .

License

Open Source License

Parameter

Parameter	Description
file	The File to compute its MD5 checksum.

Exception

Parameter	Description
IOException	Occurred Exception.

Return

The computed MD5 checksum.

Declaration

public static String computeMD5(File file) throws IOException 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright (c) 2014 Karlsruhe Institute of Technology, Germany
 *                    Technical University Darmstadt, Germany
 *                    Chalmers University of Technology, Sweden
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:/*  ww w  .  j  av a  2 s .c o  m*/
 *    Technical University Darmstadt - initial API and implementation and/or initial documentation
 *******************************************************************************/

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Main {
    /**
     * Computes the MD5 checksum of the given {@link File}.
     * @param file The {@link File} to compute its MD5 checksum.
     * @return The computed MD5 checksum.
     * @throws IOException Occurred Exception.
     */
    public static String computeMD5(File file) throws IOException {
        if (file == null) {
            throw new IOException("Can't compute MD5 without a File.");
        }
        if (!file.isFile()) {
            throw new IOException("Can't compute MD5, because \"" + file + "\" is not an existing file.");
        }
        return computeMD5(new FileInputStream(file));
    }

    /**
     * Computes the MD5 checksum of the given {@link InputStream} and closes it.
     * @param in The {@link InputStream} which provides the content to compute its MD5 checksum. The {@link InputStream} will be closed.
     * @return The computed MD5 checksum.
     * @throws IOException Occurred Exception.
     */
    public static String computeMD5(InputStream in) throws IOException {
        if (in == null) {
            throw new IOException("Can't compute MD5 without an InputStream.");
        }
        try {
            MessageDigest digest = MessageDigest.getInstance("MD5");
            byte[] buffer = new byte[8192];
            int read = 0;
            while ((read = in.read(buffer)) > 0) {
                digest.update(buffer, 0, read);
            }
            byte[] md5sum = digest.digest();
            BigInteger bigInt = new BigInteger(1, md5sum);
            return bigInt.toString(16);
        } catch (NoSuchAlgorithmException e) {
            throw new IOException("Algorithm MD5 is not available.");
        } finally {
            in.close();
        }
    }
}

Related

1. computeMD5(File file)
2. computeMD5(final File file)
3. computeMD5(String filename)
4. computeMd5Digest(final File file)