Java实现SHA1加密代码实例

/*

  * 微信公众平台(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);

     }

   }

}