SSL 之 http只用crt格式证书完成SSL单向认证通信

背景

远程调用第三方服务时，之前都是双向认证，服务器提供jks格式的keystore证书，客户端配置好即可。
今天遇到个奇葩需求，服务器只给根公钥证书(root.crt)，还是第三方合法证书，要求单向认证，客户端校验SSL握手时服务器发送的证书，只给了crt公钥。。。。真的服了。没办法，只能自己冲浪解决了，下面是针对我的这种情况，代码实践。测试没啥问题。以供搜到的你参考。

代码

//这个类实现证书校验
import javax.net.ssl.X509TrustManager;
import java.security.*;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;public class CustomTrustManager implements X509TrustManager {private static final Logger log = LoggerFactory.getLogger(CustomTrustManager.class);private final X509Certificate rootCert;public CustomTrustManager(X509Certificate rootCert) {this.rootCert = rootCert;}@Overridepublic void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {// 根据需求实现检查逻辑}@Overridepublic void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {boolean found = false;final PublicKey publicKey = rootCert.getPublicKey();for (X509Certificate cert : chain) {try {cert.verify(publicKey);found = true;break;} catch (NoSuchAlgorithmException | SignatureException | InvalidKeyException |NoSuchProviderException e) {log.error("Failed to verify client certificate", e);}}if (!found) {throw new CertificateException("No trusted certificate found in the server's certificate chain.");}}@Overridepublic X509Certificate[] getAcceptedIssuers() {return new X509Certificate[]{};}
}

测试代码

@Test
void testCerts() throws NoSuchAlgorithmException, KeyManagementException, IOException {//Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());X509Certificate certificate;//加载根证书try (InputStream inputStream = new FileInputStream("D:\\certs\\root-new.crt")) {CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");certificate = (X509Certificate) certificateFactory.generateCertificate(inputStream);} catch (IOException | java.security.cert.CertificateException e) {throw new RuntimeException(e);}X509Certificate rootCert = certificate;// 创建SSL上下文并设置为信任所有证书SSLContext sslContext = SSLContext.getInstance("TLS");sslContext.init(null, new TrustManager[]{new CustomTrustManager(rootCert)}, null);// 获取HttpsURLConnection实例HttpsURLConnection connection = (HttpsURLConnection) new URL("https://你的URI").openConnection();connection.setSSLSocketFactory(sslContext.getSocketFactory());connection.connect();System.out.println("2222222222");connection.disconnect();System.out.println("11111111111");
}

完！