package com.wx.project.util;

import java.security.MessageDigest;

/*

 * sha1 加密算法

 * 网上copy 一大堆

 */

public class SHA1 {

    private static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5',

                           '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

    /**

     * Takes the raw bytes from the digest and formats them correct.

     *

     * @param bytes the raw bytes from the digest.

     * @return the formatted bytes.

     */

    private static String getFormattedText(byte[] bytes) {

        int len = bytes.length;

        StringBuilder buf = new StringBuilder(len * 2);

        // 把密文转换成十六进制的字符串形式

        for (int j = 0; j < len; j++) {

            buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);

            buf.append(HEX_DIGITS[bytes[j] & 0x0f]);

        }

        return buf.toString();

    }

    public static String encode(String str) {

        if (str == null) {

            return null;

        }

        try {

            MessageDigest messageDigest = MessageDigest.getInstance("SHA1");

            messageDigest.update(str.getBytes());

            return getFormattedText(messageDigest.digest());

        } catch (Exception e) {

            throw new RuntimeException(e);

        }

    }

}