svn-gvsig-desktop / tags / v2_0_0_Build_2050 / extensions / org.gvsig.installer / org.gvsig.installer.lib / org.gvsig.installer.lib.impl / src / main / java / org / gvsig / installer / lib / impl / utils / MD5BinaryFileUtils.java @ 38692
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/* gvSIG. Desktop Geographic Information System.
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*
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* Copyright ? 2007-2012 gvSIG Association
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*
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* For any additional information, do not hesitate to contact us
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* at info AT gvsig.com, or visit our website www.gvsig.com.
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*/
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package org.gvsig.installer.lib.impl.utils; |
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import java.io.BufferedReader; |
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import java.io.File; |
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import java.io.FileInputStream; |
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import java.io.InputStream; |
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import java.io.InputStreamReader; |
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import java.net.URL; |
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import java.security.MessageDigest; |
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import org.slf4j.Logger; |
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import org.slf4j.LoggerFactory; |
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/**
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* @author jldominguez
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*
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*/
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public class MD5BinaryFileUtils { |
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private static final Logger LOG = LoggerFactory.getLogger(MD5BinaryFileUtils.class); |
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/**
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*
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* Gets the MD5 string of a md5 file which is associated with
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* the file provided.
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*
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* @param remote_file the file that has a ".md5" file next to it
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* @return
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*/
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public static String getMD5InRemoteFile(URL remote_file) { |
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BufferedReader in = null; |
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try {
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String _url = remote_file.toString() + ".md5"; |
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URL md5_url = new URL(_url); |
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in = new BufferedReader( |
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new InputStreamReader(md5_url.openStream())); |
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String inputLine = in.readLine();
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int space = inputLine.indexOf(" "); |
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inputLine = inputLine.substring(0, space);
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return inputLine;
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} catch (Exception ex) { |
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LOG.info("Error while reading MD5 file: " + ex.getMessage());
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return null; |
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} finally {
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try {
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in.close(); |
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} catch (Exception ex) { } |
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} |
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} |
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public static byte[] createChecksum(File the_file) throws Exception { |
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InputStream fis = new FileInputStream(the_file); |
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byte[] buffer = new byte[1024]; |
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MessageDigest complete = MessageDigest.getInstance("MD5"); |
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int numRead;
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do {
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numRead = fis.read(buffer); |
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if (numRead > 0) { |
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complete.update(buffer, 0, numRead);
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} |
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} while (numRead != -1); |
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fis.close(); |
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return complete.digest();
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} |
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/**
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* In case this is too slow for you:
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* There are faster ways to convert
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* a byte array to a HEX string
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*
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* @param the_file the input file
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* @return the given file's MD5 checksum as a hex string
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* @throws Exception
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*/
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public static String getMD5Checksum(File the_file) throws Exception { |
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byte[] b = createChecksum(the_file); |
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String result = ""; |
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for (int i=0; i < b.length; i++) { |
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result += Integer.toString( ( b[i] & 0xff ) + 0x100, 16).substring( 1 ); |
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} |
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return result;
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} |
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} |