org.springframework.util.DigestUtils Maven / Gradle / Ivy
/*
* 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.
*
* Mainly for internal use within the framework; consider
* Apache Commons Codec
* 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;
}
}