无法在HttpServletRequest中获取证书-httpServletRequest.getAttribute（“ javax.servlet.request.X509Certificate”）给出null

Question

我已经编写了启用SSL的spring boot rest服务。我想在调用服务时从http请求中提取客户端证书的公钥。

我正在尝试httpServletRequest.getAttribute("javax.servlet.request.X509Certificate"); 给出空值。

如果我尝试httpServletRequest.getAttribute("javax.servlet.request.ssl_session_mgr"); 它在包含本地证书的JSSESupport objcet中提供了SSLSession，但它是私有的，我无法提取证书。

以下是我的SSL配置（application.properties）：

server.port=8443
server.ssl.key-alias=selfsigned_localhost_sslserver
server.ssl.key-password=changeit
server.ssl.key-store=classpath:ssl-server.jks
server.ssl.key-store-provider=SUN
server.ssl.key-store-type=JKS

下面是我编写的向客户应用程序发送证书的客户端代码：

    public void testSeervice(){
    char[] passphrase = "changeit".toCharArray(); //password
            KeyStore keystore = KeyStore.getInstance("JKS");
            //KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            keystore.load(new FileInputStream("D:\\Projects\\certvalidator\\src\\main\\resources\\ssl-server.jks"), passphrase); //path

            //TrustManagerFactory tmf = TrustManagerFactory.getInstance("SunX509"); //instance
            TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            tmf.init(keystore);


            SSLContext context = SSLContext.getInstance("TLS");
            TrustManager[] trustManagers = tmf.getTrustManagers();
            context.init(null, trustManagers, null);
            SSLSocketFactory sf = context.getSocketFactory();
            URL url = new URL("https://localhost:8443/validate");

            HttpsURLConnection httpsCon = (HttpsURLConnection) url.openConnection();
            httpsCon.setSSLSocketFactory(sf);
            httpsCon.setRequestMethod("GET");

            System.out.println("Response Message is " + httpsCon.getResponseMessage());

}