001/* 002 * Copyright 2002-2016 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.util; 018 019import java.io.IOException; 020import java.io.InputStream; 021import java.security.MessageDigest; 022import java.security.NoSuchAlgorithmException; 023 024/** 025 * Miscellaneous methods for calculating digests. 026 * 027 * <p>Mainly for internal use within the framework; consider 028 * <a href="https://commons.apache.org/codec/">Apache Commons Codec</a> 029 * for a more comprehensive suite of digest utilities. 030 * 031 * @author Arjen Poutsma 032 * @author Juergen Hoeller 033 * @author Craig Andrews 034 * @since 3.0 035 */ 036public abstract class DigestUtils { 037 038 private static final String MD5_ALGORITHM_NAME = "MD5"; 039 040 private static final char[] HEX_CHARS = 041 {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; 042 043 044 /** 045 * Calculate the MD5 digest of the given bytes. 046 * @param bytes the bytes to calculate the digest over 047 * @return the digest 048 */ 049 public static byte[] md5Digest(byte[] bytes) { 050 return digest(MD5_ALGORITHM_NAME, bytes); 051 } 052 053 /** 054 * Calculate the MD5 digest of the given stream. 055 * @param inputStream the InputStream to calculate the digest over 056 * @return the digest 057 * @since 4.2 058 */ 059 public static byte[] md5Digest(InputStream inputStream) throws IOException { 060 return digest(MD5_ALGORITHM_NAME, inputStream); 061 } 062 063 /** 064 * Return a hexadecimal string representation of the MD5 digest of the given bytes. 065 * @param bytes the bytes to calculate the digest over 066 * @return a hexadecimal digest string 067 */ 068 public static String md5DigestAsHex(byte[] bytes) { 069 return digestAsHexString(MD5_ALGORITHM_NAME, bytes); 070 } 071 072 /** 073 * Return a hexadecimal string representation of the MD5 digest of the given stream. 074 * @param inputStream the InputStream to calculate the digest over 075 * @return a hexadecimal digest string 076 * @since 4.2 077 */ 078 public static String md5DigestAsHex(InputStream inputStream) throws IOException { 079 return digestAsHexString(MD5_ALGORITHM_NAME, inputStream); 080 } 081 082 /** 083 * Append a hexadecimal string representation of the MD5 digest of the given 084 * bytes to the given {@link StringBuilder}. 085 * @param bytes the bytes to calculate the digest over 086 * @param builder the string builder to append the digest to 087 * @return the given string builder 088 */ 089 public static StringBuilder appendMd5DigestAsHex(byte[] bytes, StringBuilder builder) { 090 return appendDigestAsHex(MD5_ALGORITHM_NAME, bytes, builder); 091 } 092 093 /** 094 * Append a hexadecimal string representation of the MD5 digest of the given 095 * inputStream to the given {@link StringBuilder}. 096 * @param inputStream the inputStream to calculate the digest over 097 * @param builder the string builder to append the digest to 098 * @return the given string builder 099 * @since 4.2 100 */ 101 public static StringBuilder appendMd5DigestAsHex(InputStream inputStream, StringBuilder builder) throws IOException { 102 return appendDigestAsHex(MD5_ALGORITHM_NAME, inputStream, builder); 103 } 104 105 106 /** 107 * Create a new {@link MessageDigest} with the given algorithm. 108 * Necessary because {@code MessageDigest} is not thread-safe. 109 */ 110 private static MessageDigest getDigest(String algorithm) { 111 try { 112 return MessageDigest.getInstance(algorithm); 113 } 114 catch (NoSuchAlgorithmException ex) { 115 throw new IllegalStateException("Could not find MessageDigest with algorithm \"" + algorithm + "\"", ex); 116 } 117 } 118 119 private static byte[] digest(String algorithm, byte[] bytes) { 120 return getDigest(algorithm).digest(bytes); 121 } 122 123 private static byte[] digest(String algorithm, InputStream inputStream) throws IOException { 124 MessageDigest messageDigest = getDigest(algorithm); 125 if (inputStream instanceof UpdateMessageDigestInputStream){ 126 ((UpdateMessageDigestInputStream) inputStream).updateMessageDigest(messageDigest); 127 return messageDigest.digest(); 128 } 129 else { 130 final byte[] buffer = new byte[StreamUtils.BUFFER_SIZE]; 131 int bytesRead = -1; 132 while ((bytesRead = inputStream.read(buffer)) != -1) { 133 messageDigest.update(buffer, 0, bytesRead); 134 } 135 return messageDigest.digest(); 136 } 137 } 138 139 private static String digestAsHexString(String algorithm, byte[] bytes) { 140 char[] hexDigest = digestAsHexChars(algorithm, bytes); 141 return new String(hexDigest); 142 } 143 144 private static String digestAsHexString(String algorithm, InputStream inputStream) throws IOException { 145 char[] hexDigest = digestAsHexChars(algorithm, inputStream); 146 return new String(hexDigest); 147 } 148 149 private static StringBuilder appendDigestAsHex(String algorithm, byte[] bytes, StringBuilder builder) { 150 char[] hexDigest = digestAsHexChars(algorithm, bytes); 151 return builder.append(hexDigest); 152 } 153 154 private static StringBuilder appendDigestAsHex(String algorithm, InputStream inputStream, StringBuilder builder) 155 throws IOException { 156 157 char[] hexDigest = digestAsHexChars(algorithm, inputStream); 158 return builder.append(hexDigest); 159 } 160 161 private static char[] digestAsHexChars(String algorithm, byte[] bytes) { 162 byte[] digest = digest(algorithm, bytes); 163 return encodeHex(digest); 164 } 165 166 private static char[] digestAsHexChars(String algorithm, InputStream inputStream) throws IOException { 167 byte[] digest = digest(algorithm, inputStream); 168 return encodeHex(digest); 169 } 170 171 private static char[] encodeHex(byte[] bytes) { 172 char[] chars = new char[32]; 173 for (int i = 0; i < chars.length; i = i + 2) { 174 byte b = bytes[i / 2]; 175 chars[i] = HEX_CHARS[(b >>> 0x4) & 0xf]; 176 chars[i + 1] = HEX_CHARS[b & 0xf]; 177 } 178 return chars; 179 } 180 181}