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/* * Copyright 2002-2016 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.util; import java.io.IOException; import java.io.InputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; /** * Miscellaneous methods for calculating digests. * * <p>Mainly for internal use within the framework; consider * <a href="https://commons.apache.org/codec/">Apache Commons Codec</a> * for a more comprehensive suite of digest utilities. * * @author Arjen Poutsma * @author Juergen Hoeller * @author Craig Andrews * @since 3.0 */ public abstract class DigestUtils { private static final String MD5_ALGORITHM_NAME = "MD5"; private static final char[] HEX_CHARS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; /** * Calculate the MD5 digest of the given bytes. * @param bytes the bytes to calculate the digest over * @return the digest */ public static byte[] md5Digest(byte[] bytes) { return digest(MD5_ALGORITHM_NAME, bytes); } /** * Calculate the MD5 digest of the given stream. * @param inputStream the InputStream to calculate the digest over * @return the digest * @since 4.2 */ public static byte[] md5Digest(InputStream inputStream) throws IOException { return digest(MD5_ALGORITHM_NAME, inputStream); } /** * Return a hexadecimal string representation of the MD5 digest of the given bytes. * @param bytes the bytes to calculate the digest over * @return a hexadecimal digest string */ public static String md5DigestAsHex(byte[] bytes) { return digestAsHexString(MD5_ALGORITHM_NAME, bytes); } /** * Return a hexadecimal string representation of the MD5 digest of the given stream. * @param inputStream the InputStream to calculate the digest over * @return a hexadecimal digest string * @since 4.2 */ public static String md5DigestAsHex(InputStream inputStream) throws IOException { return digestAsHexString(MD5_ALGORITHM_NAME, inputStream); } /** * Append a hexadecimal string representation of the MD5 digest of the given * bytes to the given {@link StringBuilder}. * @param bytes the bytes to calculate the digest over * @param builder the string builder to append the digest to * @return the given string builder */ public static StringBuilder appendMd5DigestAsHex(byte[] bytes, StringBuilder builder) { return appendDigestAsHex(MD5_ALGORITHM_NAME, bytes, builder); } /** * Append a hexadecimal string representation of the MD5 digest of the given * inputStream to the given {@link StringBuilder}. * @param inputStream the inputStream to calculate the digest over * @param builder the string builder to append the digest to * @return the given string builder * @since 4.2 */ public static StringBuilder appendMd5DigestAsHex(InputStream inputStream, StringBuilder builder) throws IOException { return appendDigestAsHex(MD5_ALGORITHM_NAME, inputStream, builder); } /** * Create a new {@link MessageDigest} with the given algorithm. * Necessary because {@code MessageDigest} is not thread-safe. */ private static MessageDigest getDigest(String algorithm) { try { return MessageDigest.getInstance(algorithm); } catch (NoSuchAlgorithmException ex) { throw new IllegalStateException("Could not find MessageDigest with algorithm \"" + algorithm + "\"", ex); } } private static byte[] digest(String algorithm, byte[] bytes) { return getDigest(algorithm).digest(bytes); } private static byte[] digest(String algorithm, InputStream inputStream) throws IOException { MessageDigest messageDigest = getDigest(algorithm); if (inputStream instanceof UpdateMessageDigestInputStream) { ((UpdateMessageDigestInputStream) inputStream).updateMessageDigest(messageDigest); return messageDigest.digest(); } else { final byte[] buffer = new byte[StreamUtils.BUFFER_SIZE]; int bytesRead = -1; while ((bytesRead = inputStream.read(buffer)) != -1) { messageDigest.update(buffer, 0, bytesRead); } return messageDigest.digest(); } } private static String digestAsHexString(String algorithm, byte[] bytes) { char[] hexDigest = digestAsHexChars(algorithm, bytes); return new String(hexDigest); } private static String digestAsHexString(String algorithm, InputStream inputStream) throws IOException { char[] hexDigest = digestAsHexChars(algorithm, inputStream); return new String(hexDigest); } private static StringBuilder appendDigestAsHex(String algorithm, byte[] bytes, StringBuilder builder) { char[] hexDigest = digestAsHexChars(algorithm, bytes); return builder.append(hexDigest); } private static StringBuilder appendDigestAsHex(String algorithm, InputStream inputStream, StringBuilder builder) throws IOException { char[] hexDigest = digestAsHexChars(algorithm, inputStream); return builder.append(hexDigest); } private static char[] digestAsHexChars(String algorithm, byte[] bytes) { byte[] digest = digest(algorithm, bytes); return encodeHex(digest); } private static char[] digestAsHexChars(String algorithm, InputStream inputStream) throws IOException { byte[] digest = digest(algorithm, inputStream); return encodeHex(digest); } private static char[] encodeHex(byte[] bytes) { char[] chars = new char[32]; for (int i = 0; i < chars.length; i = i + 2) { byte b = bytes[i / 2]; chars[i] = HEX_CHARS[(b >>> 0x4) & 0xf]; chars[i + 1] = HEX_CHARS[b & 0xf]; } return chars; } }