非对称加密算法java

public class GetSignFuncImpl implements GetSignFunc {

    private static final int MAX_ENCRYPT_BLOCK = 117;

    private static final int MAX_DECRYPT_BLOCK = 128;

    private static final String PUBLIC_KEY = "213213213213123dsvdvdsfdsfdsfsf";

    @Override
    public GetSignResponse execute(GetGignRequest getGignRequest) {
        GetSignResponse resp = new GetSignResponse();
        try {
            Map sortedBody = new TreeMap<>(transformBeanToMap(getGignRequest));
            Log.info("参与签名的数据 : {}", Json.toJson(sortedBody));
            String bodyString = sortedBody.entrySet().stream().map(entry -> entry.getKey() + "=" + entry.getValue())
                    .collect(Collectors.joining("&"));
            byte[] keyBytes;
            if(StringUtil.isNotBlank(getGignRequest.getPublicKey()) && StringUtil.isNotEmpty(getGignRequest.getPublicKey())){
                keyBytes = Base64.decodeBase64(getGignRequest.getPublicKey());
            }else{
                keyBytes = Base64.decodeBase64(PUBLIC_KEY);
            }
            RSAPublicKey rsaPublicKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(keyBytes));
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE, rsaPublicKey);
            byte[] data = bodyString.getBytes(StandardCharsets.UTF_8);
            int inputLen = data.length;
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            int offSet = 0;
            byte[] cache;
            int i = 0;
            while (inputLen - offSet > 0) {
                if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                    cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
                } else {
                    cache = cipher.doFinal(data, offSet, inputLen - offSet);
                }
                out.write(cache, 0, cache.length);
                i++;
                offSet = i * MAX_ENCRYPT_BLOCK;
            }
            byte[] encryptedData = out.toByteArray();
            out.close();
            Log.info("sign : {}", Base64.encodeBase64String(encryptedData));
            resp.setSign(Base64.encodeBase64String(encryptedData));
        } catch (Exception e) {
            throw new BusinessException("");
        }
        return resp;
    }