使用 SSLSocketFactory 的 HttpsURLConnection 发生 UnknownHostException

Question

我正在尝试使用 API，但我需要上传证书才能使用它。

这就是我一直在尝试使用 API 的内容。在此方法中，我打开连接以使用 API：

public static String consumeAPI() {
  String respAPI = "";
  String param = "some_param";
  String user = "user";
  String pswrd = "pass";
  try {
    SSLSocketFactory ssl = createSSLSocketFactory("path_of_cert");
    URL url = new URL("https://api-dir.com.es:8080/api");
    HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
    conn.setSSLSocketFactory(ssl);
    conn.setDoOutput(true);
    conn.setRequestMethod("POST");
    conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
    conn.setRequestProperty("Authorization", "Basic " + Base64.getEncoder().encodeToString((user + ":" + pswrd).getBytes(StandardCharsets.UTF_8)));
    conn.setConnectTimeout(APIUtils.TIMEOUT);
    try (OutputStream os = conn.getOutputStream()) {
      os.write(parametros.getBytes(StandardCharsets.UTF_8));
      os.flush();
      if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
        try (BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8))) {
          StringBuilder result = new StringBuilder();
          String auxStr;
          while ((auxStr = br.readLine()) != null) {
            result.append(auxStr);
          }
          respAPI = result.toString();
        }
      }
    }
    return respAPI;
  }
  catch(IOException | ClassCastException | IllegalStateException | IllegalArgumentException e) {
    e.printStackTrace();
    return null;
  }
}

这是生成加载了证书的

SSLSocketFactory

的方法：

private static SSLSocketFactory createSSLSocketFactory(String certPath) {
  try {
    try (InputStream in =APIUtils.class.getResourceAsStream(certPath)) {
      Certificate certificate = CertificateFactory.getInstance("X.509").generateCertificate( in );
      KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
      keyStore.load(null);
      keyStore.setCertificateEntry("certalias", certificate);
      TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
      trustManagerFactory.init(keyStore);
      SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
      sslContext.init(null, trustManagerFactory.getTrustManagers(), null);
      return sslContext.getSocketFactory();
    }
  }
  catch(CertificateException | KeyStoreException | NoSuchAlgorithmException | IOException | KeyManagementException e) {
    e.printStackTrace();
    return null;
  }
}

但是它抛出了

java.net.UnknownHostException

，这是错误跟踪：

java.net.UnknownHostException: api-dir.com.es
        at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:567)
        at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)
        at java.base/java.net.Socket.connect(Socket.java:633)
        at java.base/sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:304)
        at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:178)
        at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:532)
        at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:637)
        at java.base/sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:266)
        at java.base/sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:380)
        at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:193)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1242)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1128)
        at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:179)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.getOutputStream0(HttpURLConnection.java:1430)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1401)
        at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:220)
        at deployment.regional.war//com.ekt.regional.web.api.SomeAPI.consumeAPI(SomeAPI.java:49)

我确保 API url 正确并且我们有访问它的权限。

值得一提的是，证书是一个

.crt

文件，是针对开发环境的。

Answer 1

这是DNS解析错误

API调用需要代理吗？您可能需要在通话中添加 http 代理。

取决于操作系统 你可以跑 在 Windows 上

ping  api-dir.com.es 
or tracert api-dir.com.es   

或Linux

traceroute api-dir.com.es  

查看您是否可以连接到此服务/api

或者尝试提供 api-dir.com.es 的直接 IP，而不是 URL 中的名称

或尝试在主机文件中创建 IP 条目

Linux

/etc/host

窗户

c:\Windows\System32\Drivers\etc\hosts

输入为

api-dir.com.es IP 地址