/*
 * 微信公眾平臺(JAVA) SDK
 *
 * Copyright (c) 2016, Ansitech Network Technology Co.,Ltd All rights reserved.
 * http://www.ansitech.com/weixin/sdk/
 *
 * 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
 *
 *   http://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 com.levi.utils;
 
import java.security.MessageDigest;
 
/**
 * <p>Title: SHA1算法</p>
 *
 * @author levi
 */
public final 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);
    // 把密文轉換成十六進制的字符串形式
    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);
    }
  }
}