接口调用代码：

CloseableHttpClient httpClient = WxHttpClient.createHttpClient();
HttpGet httpGet = new HttpGet("https://api.mch.weixin.qq.com/v3/applyment4sub/applyment/business_code/" + businessCode);
httpGet.addHeader("Accept", "application/json");
httpGet.addHeader("Content-type", "application/json; charset=utf-8");
CloseableHttpResponse response = httpClient.execute(httpGet);
HttpEntity entity = response.getEntity();
WxAuthStatusResponse res = JSONObject.parseObject(EntityUtils.toString(entity), WxAuthStatusResponse.class);

工具类代码：

public class WxHttpClient {
    // 设置VX证书默认参数
    // 服务商Id
    private static final String merchantId = "163...";
    // API V3密钥
    private static final String apiV3Key = "zL3gprVKrr05...";
    // 证书序列号
    public static final String serialNumber = "2DD9DABDD05...";

    public static CloseableHttpClient createHttpClient() {
        PrivateKey privateKey = createPrivateKey();
        Verifier verifier = createVerifier(privateKey);
        WechatPayHttpClientBuilder builder = WechatPayHttpClientBuilder.create()
                .withMerchant(merchantId, serialNumber, privateKey)
                .withValidator(new WechatPay2Validator(verifier));
        return builder.build();
    }

    public static PrivateKey createPrivateKey() {
        InputStream inputStream = ResourceUtil.getStream("wx_pay/apiclient_key.pem");
        return PemUtil.loadPrivateKey(inputStream);
    }

    public static Verifier createVerifier(PrivateKey privateKey) {
        try {
            CertificatesManager instance = CertificatesManager.getInstance();
            instance.putMerchant(merchantId, new WechatPay2Credentials(
                    merchantId, new PrivateKeySigner(serialNumber, privateKey)), apiV3Key.getBytes(StandardCharsets.UTF_8));
            return instance.getVerifier(merchantId);
        } catch (GeneralSecurityException | NotFoundException | IOException | HttpCodeException e) {
            e.printStackTrace();
        }
        return null;
    }
}

响应返回内容：

c.w.pay.contrib.apache.httpclient.SignatureExec > 应答的状态码不为200-299。status code[400] request headers[[Accept: application/json, Content-type: application/json; charset=utf-8, Authorization: WECHATPAY2-SHA256-RSA2048 mchid="1638262312",nonce_str="4X2TDkZuX94X55pxWoeaezI0rsSDvkZk",timestamp="1677857507",serial_no="2DD9DAB...",signature="tFEwJ6qmBCmmbADju/7VqtdL7vXsb8URSdsw69HwNVtRGyUcJASdyY391bOnjVB11SDR5t/a1uC+XhRalrwQN2IDJiJPWpL0OEZR7aKea5MV0YIgkmkldiDS3V8VgrBnuGAaTCDovgkHOrDibN6sVoy16zZmTAEGxCf5Vr/lUOsDa5IkfqdgsB7E25ZzCli4M4g7sKldOiGhUEVSynFEAbW9n3kgmjntlwKaoyU6D9ABSz5k8eGMGc4wO/EFGZQEnHj3SwLufB2xV1ub1ZkBrUv3fwau1BXiN1EwQ0Dxwmj/XVx6XXeJ7Tt4K9AKj1GJdnxBPPu1PbHdVZtL/jmPSQ==", Host: api.mch.weixin.qq.com, Connection: Keep-Alive, User-Agent: WechatPay-Apache-HttpClient/0.4.7 (Mac OS X/10.16) Java/1.8.0_322, Accept-Encoding: gzip,deflate]]