SHA-256加密

package com.itmoll.yinlianpay.until;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * SHA256加密
 *
 */
public class SHA256Util {

    public static final String KEY_ALGORITHM = "SHA-256";
    public static final String ENCODE = "UTF-8";

    /**
     * 利用java原生的类实现SHA256加密
     *
     * @param str 参数拼接的字符串
     * @return
     */
    public static String sign(String str) {
        try {
            MessageDigest messageDigest = MessageDigest.getInstance(KEY_ALGORITHM);
            messageDigest.update(str.getBytes(ENCODE));
            byte[] bytes = messageDigest.digest();

            StringBuffer stringBuffer = new StringBuffer();
            String temp = null;
            // 将byte转为16进制
            for (int i = 0; i < bytes.length; i++) {
                temp = Integer.toHexString(bytes[i] & 0xFF);
                if (temp.length() == 1) {
                    // 1得到一位的进行补0操作
                    stringBuffer.append("0");
                }
                stringBuffer.append(temp);
            }
            return stringBuffer.toString();
        } catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     *  验证签名
     * @param str 待签名字符串
     * @param sign 待验证签名
     * @return true通过，false不通过
     */
    public static boolean verifySign(String str, String sign) throws Exception {
        boolean flag = false;
        String tmpSign = sign(str.trim());
        flag = tmpSign.equals(sign.trim());
        return flag;
    }
}