Android -使用公有crt和私有pem文件连接后端服务器

// 加载公有crt文件
InputStream inputStream = getResources().openRawResource(R.raw.public_crt);
CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
X509Certificate certificate = (X509Certificate) certificateFactory.generateCertificate(inputStream);

// 创建信任管理器
KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
keyStore.load(null, null);
keyStore.setCertificateEntry("ca", certificate);
TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
trustManagerFactory.init(keyStore);

// 创建SSL套接字工厂
SSLContext sslContext = SSLContext.getInstance("TLS");
sslContext.init(null, trustManagerFactory.getTrustManagers(), null);
SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();

// 连接后端服务器
URL url = new URL("https://example.com");
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
connection.setSSLSocketFactory(sslSocketFactory);
connection.connect();