RestTemplate 調用Https報錯 unable to find valid certification path to requested target

問題描述：Spring Boot項目中使用RestTemplate調用https接口出現以下錯誤

sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

問題原因：Java自帶的安全證書不受信任，在代碼里面的實現方式為在構建restTemplate時忽略證書，繞開SSL驗證，解決代碼如下代碼如下：

import org.springframework.http.client.SimpleClientHttpRequestFactory;

import javax.net.ssl.*;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;

/**
 * 跳過證書驗證封裝
 */
public class SSL extends SimpleClientHttpRequestFactory {

    @Override
    protected void prepareConnection(HttpURLConnection connection, String httpMethod)
            throws IOException {
        if (connection instanceof HttpsURLConnection) {
            prepareHttpsConnection((HttpsURLConnection) connection);
        }
        super.prepareConnection(connection, httpMethod);
    }

    private void prepareHttpsConnection(HttpsURLConnection connection) {
        connection.setHostnameVerifier(new SkipHostnameVerifier());
        try {
            connection.setSSLSocketFactory(createSslSocketFactory());
        }
        catch (Exception ex) {
            // Ignore
        }
    }

    private SSLSocketFactory createSslSocketFactory() throws Exception {
        SSLContext context = SSLContext.getInstance("TLS");
        context.init(null, new TrustManager[] { new SkipX509TrustManager() },
                new SecureRandom());
        return context.getSocketFactory();
    }

    private class SkipHostnameVerifier implements HostnameVerifier {

        @Override
        public boolean verify(String s, SSLSession sslSession) {
            return true;
        }

    }

    private static class SkipX509TrustManager implements X509TrustManager {

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

        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType) {
        }

        @Override
        public void checkServerTrusted(X509Certificate[] chain, String authType) {
        }

    }

}

@Configuration
public class RestTemplateConfig {

    @Bean
    public RestTemplate restTemplate(ClientHttpRequestFactory factory) {
        return new RestTemplate(factory);
    }

    @Bean
    public ClientHttpRequestFactory simpleClientHttpRequestFactory() {
        SSL factory = new SSL();
        factory.setReadTimeout(5000);
        factory.setConnectTimeout(15000);
        return factory;
    }


}