java.security.cert.CertPathValidatorException を解決してください。認証パスのトラストアンカーが見つかりませんでした。

オプション1

try {
  CertificateFactory cf = CertificateFactory.getInstance("X.509");
  // uwca.crt is packaged in asset, the certificate can be downloaded from https://itconnect.uw.edu/security/securing-computer/install/safari-os-x/下载
  InputStream caInput = new BufferedInputStream(getAssets().open("uwca.crt"));
  Certificate ca;
  try {
      ca = cf.generateCertificate(caInput);
      Log.i("Longer", "ca=" + ((X509Certificate) ca).getSubjectDN());
      Log.i("Longer", "key=" + ((X509Certificate) ca).getPublicKey();
  } finally {
      caInput.close();
  }

  // Create a KeyStore containing our trusted CAs
  String keyStoreType = KeyStore.getDefaultType();
  KeyStore keyStore = KeyStore.getInstance(keyStoreType);
  keyStore.load(null, null);
  keyStore.setCertificateEntry("ca", ca);

  // Create a TrustManager that trusts the CAs in our KeyStore
  String tmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm();
  TrustManagerFactory tmf = TrustManagerFactory.getInstance(tmfAlgorithm);
  tmf.init(keyStore);

  // Create an SSLContext that uses our TrustManager
  SSLContext context = SSLContext.getInstance("TLSv1","AndroidOpenSSL");
  context.init(null, tmf.getTrustManagers(), null);

  URL url = new URL("https://certs.cac.washington.edu/CAtest/");
  HttpsURLConnection urlConnection =
          (HttpsURLConnection)url.openConnection();
  urlConnection.setSSLSocketFactory(context.getSocketFactory());
  InputStream in = urlConnection.getInputStream();
  copyInputStreamToOutputStream(in, System.out);
} catch (CertificateException e) {
  e.printStackTrace();
} catch (IOException e) {
  e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
  e.printStackTrace();
} catch (KeyStoreException e) {
  e.printStackTrace();
} catch (KeyManagementException e) {
  e.printStackTrace();
} catch (NoSuchProviderException e) {
  e.printStackTrace();
}

シナリオ2

オプション 1 と同様に、アプリ内に証明書をパックしますが、KeyStore を介して生成された TrustManager をブートストラップするのではなく、単に TrustManager を直接カスタマイズして、チェックサムロジックを自分で実装します。

-サーバ証明書の有効期限が切れているかどうか。
-証明書の署名が正当であるか

try {
  CertificateFactory cf = CertificateFactory.getInstance("X.509");
  // uwca.crt is packaged in asset, the certificate can be downloaded from https://itconnect.uw.edu/security/securing-computer/install/safari-os-x/下载
  InputStream caInput = new BufferedInputStream(getAssets().open("uwca.crt"));
  final Certificate ca;
  try {
      ca = cf.generateCertificate(caInput);
      Log.i("Longer", "ca=" + ((X509Certificate) ca).getSubjectDN());
      Log.i("Longer", "key=" + ((X509Certificate) ca).getPublicKey());
  } finally {
      caInput.close();
  }
  // Create an SSLContext that uses our TrustManager
  SSLContext context = SSLContext.getInstance("TLSv1","AndroidOpenSSL");
  context.init(null, new TrustManager[]{
          new X509TrustManager() {
              @Override
              public void checkClientTrusted(X509Certificate[] chain,
                      String authType)
                      throws CertificateException {

              }

              @Override
              public void checkServerTrusted(X509Certificate[] chain,
                      String authType)
                      throws CertificateException {
                  for (X509Certificate cert : chain) {

                      // Make sure that it hasn't expired.
                      cert.checkValidity();

                      // Verify the certificate's public key chain.
                      try {
                          cert.verify(((X509Certificate) ca).getPublicKey());
                      } catch (NoSuchAlgorithmException e) {
                          e.printStackTrace();
                      } catch (InvalidKeyException e) {
                          e.printStackTrace();
                      } catch (NoSuchProviderException e) {
                          e.printStackTrace();
                      } catch (SignatureException e) {
                          e.printStackTrace();
                      }
                  }
              }

              @Override
              public X509Certificate[] getAcceptedIssuers() {
                  return new X509Certificate[0];
              }
          }
  }, null);

  URL url = new URL("https://certs.cac.washington.edu/CAtest/");
  HttpsURLConnection urlConnection =
          (HttpsURLConnection)url.openConnection();
  urlConnection.setSSLSocketFactory(context.getSocketFactory());
  InputStream in = urlConnection.getInputStream();
  copyInputStreamToOutputStream(in, System.out);
} catch (CertificateException e) {
  e.printStackTrace();
} catch (IOException e) {
  e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
  e.printStackTrace();
} catch (KeyManagementException e) {
  e.printStackTrace();
} catch (NoSuchProviderException e) {
  e.printStackTrace();
}

シナリオ3（推奨） 

    //Certificate trust
    public final static HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() {
        public boolean verify(String hostname, SSLSession session) {
            return true;
        }
    };
//certificate trust
//key code
if (url.getProtocol().toUpperCase().equals("HTTPS")) {
        trustAllHosts();
        HttpsURLConnection https = (HttpsURLConnection) url
                .openConnection();
        https.setHostnameVerifier(DO_NOT_VERIFY);
        conn = https;
    } else {
        conn = (HttpURLConnection) url.openConnection();
    }
// key code

    public static void trustAllHosts() {
        TrustManager[] trustAllCerts = new TrustManager[]{new X509TrustManager() {
            public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                return new java.security.cert.X509Certificate[]{};
            }

            public void checkClientTrusted(X509Certificate[] chain,
                                           String authType) throws CertificateException {
            }

            public void checkServerTrusted(X509Certificate[] chain,
                                           String authType) throws CertificateException {
            }
        }};
        // Install the all-trusting trust manager
        try {
            SSLContext sc = SSLContext.getInstance("TLS");
            sc.init(null, trustAllCerts, new java.security.SecureRandom());
            HttpsURLConnection
                    .setDefaultSSLSocketFactory(sc.getSocketFactory());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }