com.github.fartherp.framework.common.util.RedisDigestUtils Maven / Gradle / Ivy

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/*
 * Copyright (c) 2018. CK. All rights reserved.
 */

package com.github.fartherp.framework.common.util;

import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Created by IntelliJ IDEA.
 *
 * @author: CK
 * @date: 2018/5/31
 */
public class RedisDigestUtils {
    private static final char[] HEX_CHARS = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
            'a', 'b', 'c', 'd', 'e', 'f'};

    private static final Charset UTF8_CHARSET = Charset.forName("UTF8");

    /**
     * Returns the SHA1 of the provided data
     *
     * @param data The data to calculate, such as the contents of a file
     * @return The human-readable SHA1
     */
    public static String sha1DigestAsHex(String data) {
        byte[] dataBytes = getDigest("SHA").digest(data.getBytes(UTF8_CHARSET));
        return new String(encodeHex(dataBytes));
    }

    private static char[] encodeHex(byte[] data) {
        int l = data.length;
        char[] out = new char[l << 1];
        for (int i = 0, j = 0; i < l; i++) {
            out[j++] = HEX_CHARS[(0xF0 & data[i]) >>> 4];
            out[j++] = HEX_CHARS[0x0F & data[i]];
        }
        return out;
    }

    /**
     * Creates 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);
        }
    }
}