root / branches / v2_0_0_prep / extensions / org.gvsig.installer / org.gvsig.installer.lib / org.gvsig.installer.lib.impl / src / main / java / org / gvsig / installer / lib / impl / utils / MD5BinaryFileUtils.java @ 38600
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1 | 38435 | jldominguez | /* gvSIG. Desktop Geographic Information System.
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2 | *
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3 | * Copyright ? 2007-2012 gvSIG Association
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4 | *
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5 | * This program is free software; you can redistribute it and/or
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6 | * modify it under the terms of the GNU General Public License
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7 | * as published by the Free Software Foundation; either version 2
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8 | * of the License, or (at your option) any later version.
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9 | *
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10 | * This program is distributed in the hope that it will be useful,
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11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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13 | * GNU General Public License for more details.
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14 | *
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15 | * You should have received a copy of the GNU General Public License
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16 | * along with this program; if not, write to the Free Software
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17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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18 | * MA 02110-1301, USA.
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19 | *
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20 | * For any additional information, do not hesitate to contact us
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21 | * at info AT gvsig.com, or visit our website www.gvsig.com.
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22 | */
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23 | package org.gvsig.installer.lib.impl.utils; |
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24 | |||
25 | import java.io.BufferedReader; |
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26 | import java.io.File; |
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27 | import java.io.FileInputStream; |
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28 | import java.io.InputStream; |
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29 | import java.io.InputStreamReader; |
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30 | import java.net.URL; |
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31 | import java.security.MessageDigest; |
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32 | |||
33 | import org.slf4j.Logger; |
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34 | import org.slf4j.LoggerFactory; |
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35 | |||
36 | |||
37 | /**
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38 | * @author jldominguez
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39 | *
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40 | */
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41 | 38540 | jldominguez | public class MD5BinaryFileUtils { |
42 | 38435 | jldominguez | |
43 | 38540 | jldominguez | private static final Logger LOG = LoggerFactory.getLogger(MD5BinaryFileUtils.class); |
44 | 38435 | jldominguez | |
45 | /**
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46 | *
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47 | * Gets the MD5 string of a md5 file which is associated with
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48 | * the file provided.
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49 | *
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50 | * @param remote_file the file that has a ".md5" file next to it
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51 | * @return
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52 | */
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53 | public static String getMD5InRemoteFile(URL remote_file) { |
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54 | |||
55 | BufferedReader in = null; |
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56 | try {
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57 | String _url = remote_file.toString() + ".md5"; |
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58 | URL md5_url = new URL(_url); |
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59 | |||
60 | in = new BufferedReader( |
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61 | new InputStreamReader(md5_url.openStream())); |
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62 | String inputLine = in.readLine();
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63 | |||
64 | int space = inputLine.indexOf(" "); |
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65 | inputLine = inputLine.substring(0, space);
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66 | return inputLine;
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67 | } catch (Exception ex) { |
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68 | LOG.info("Error while reading MD5 file: " + ex.getMessage());
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69 | return null; |
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70 | } finally {
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71 | try {
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72 | in.close(); |
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73 | } catch (Exception ex) { } |
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74 | } |
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75 | |||
76 | } |
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77 | |||
78 | public static byte[] createChecksum(File the_file) throws Exception { |
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79 | |||
80 | InputStream fis = new FileInputStream(the_file); |
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81 | |||
82 | byte[] buffer = new byte[1024]; |
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83 | MessageDigest complete = MessageDigest.getInstance("MD5"); |
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84 | int numRead;
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85 | |||
86 | do {
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87 | numRead = fis.read(buffer); |
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88 | if (numRead > 0) { |
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89 | complete.update(buffer, 0, numRead);
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90 | } |
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91 | } while (numRead != -1); |
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92 | |||
93 | fis.close(); |
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94 | return complete.digest();
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95 | } |
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96 | |||
97 | 38540 | jldominguez | /**
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98 | * In case this is too slow for you:
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99 | * There are faster ways to convert
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100 | * a byte array to a HEX string
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101 | *
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102 | * @param the_file the input file
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103 | * @return the given file's MD5 checksum as a hex string
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104 | * @throws Exception
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105 | */
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106 | 38435 | jldominguez | public static String getMD5Checksum(File the_file) throws Exception { |
107 | byte[] b = createChecksum(the_file); |
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108 | String result = ""; |
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109 | |||
110 | for (int i=0; i < b.length; i++) { |
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111 | result += Integer.toString( ( b[i] & 0xff ) + 0x100, 16).substring( 1 ); |
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112 | } |
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113 | return result;
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114 | } |
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115 | |||
116 | } |