package com.util;

/**

 * @author wangxiangyu

 * @date：2017年10月16日 上午9:00:47

 * 类说明：SHA签名算法

 */

public class SHAHelper {

    private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5","6", "7", "8", "9", "A", "B", "C", "D", "E", "F"};

    /**

     * 转换字节数组为16进制字串

     *

     * @param b 字节数组

     * @return 16进制字串

     */

    public static String byteArrayToHexString(byte[] b) {

        StringBuffer resultSb = new StringBuffer();

        for (int i = 0; i < b.length; i++) {

            resultSb.append(byteToHexString(b[i]));

        }

        return resultSb.toString();

    }

    private static String byteToHexString(byte b) {

        int n = b;

        if (n < 0)

            n = 256 + n;

        int d1 = n / 16;

        int d2 = n % 16;

        return hexDigits[d1] + hexDigits[d2];

    }

    /**

     * SHA摘要计算(byte[]).

     *

     * @param src byte[]

     * @throws Exception

     * @return byte[] 16 bit digest

     */

    public static byte[] SHADigest(byte[] src) throws Exception {

        java.security.MessageDigest alg = java.security.MessageDigest

                .getInstance("SHA");

        return alg.digest(src);

    }

    /**

     * SHA摘要计算(String).

     *

     * @param src String型的目标串

     * @throws Exception

     * @return String

     */

    public static String SHADigest(String src) throws Exception {

        return byteArrayToHexString(SHADigest(src.getBytes("UTF-8")));

    }

    /** Test crypt */

    public static void main(String[] args) {

        try {

            // 获得的明文数据

            String serialNumber = "0101102010031723101273807F00179E";

            String reqBizArgs = "<ReqBizArgs version='1'><test>test</test></ReqBizArgs>";

            String key = "8204CDBD76BB69DAE040007F010017A4";

            String desStr = serialNumber + reqBizArgs + key;

            System.out.println("原文串 desStr = '" + desStr + "'");

            // 生成Signature

            String signature = SHADigest(desStr);

            System.out.println("签名串Signature = '" + signature + "'");

        } catch (Exception ex) {

            ex.printStackTrace();

        }

    }

}