如何使用带证书身份验证的RestTemplate？

import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManagerFactory;
import java.io.FileInputStream;
import java.security.KeyStore;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;

public class Main {
    public static void main(String[] args) throws Exception {
        // 1. 准备证书
        String certificatePath = "/path/to/certificate.pem";

        // 2. 创建KeyStore
        KeyStore keyStore = KeyStore.getInstance("PKCS12");
        keyStore.load(null, null);

        // 3. 加载证书到KeyStore
        CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
        X509Certificate certificate = (X509Certificate) certificateFactory.generateCertificate(new FileInputStream(certificatePath));
        keyStore.setCertificateEntry("alias", certificate);

        // 4. 创建SSL上下文
        TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
        trustManagerFactory.init(keyStore);
        SSLContext sslContext = SSLContext.getInstance("TLS");
        sslContext.init(null, trustManagerFactory.getTrustManagers(), null);

        // 5. 配置RestTemplate
        HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
        requestFactory.setHttpClient(HttpClients.custom().setSSLContext(sslContext).build());
        RestTemplate restTemplate = new RestTemplate(requestFactory);

        // 6. 发送请求
        String url = "https://api.example.com";
        String response = restTemplate.getForObject(url, String.class);
        System.out.println(response);
    }
}