spring RestTemplate 发起https请求 Received fatal alert: protocol_version； 异常解决

org.springframework.web.client.ResourceAccessException: I/O error on POST request for "https://yxt.ngrok.cn/api/notify": Received fatal alert: protocol_version; nested exception is javax.net.ssl.SSLException: Received fatal alert: protocol_version
 at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:748) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
 at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:674) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
 at org.springframework.web.client.RestTemplate.postForEntity(RestTemplate.java:449) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]

使用RestTemplate发起https请求需要配置ClientHttpRequestFactory

RestTemplate restTemplate = new RestTemplate(new HttpsClientRequestFactory());

注意两个地方：
1） SSLContext sslContext = SSLContext.getInstance(“TLSv1.2”); 协议版本为1.2
2） ((SSLSocket) socket).setEnabledProtocols(new String[]{“TLSv1”, “TLSv1.1”, “TLSv1.2”}); 兼容支持协议版本

如下：

import org.springframework.http.client.SimpleClientHttpRequestFactory;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.InetAddress;
import java.net.Socket;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;

/**
 * HTTPS请求
 *
 * @author Yang douya
 * @date 2021/2/3 10:53
 */
public class HttpsClientRequestFactory extends SimpleClientHttpRequestFactory {

    @Override
    protected void prepareConnection(HttpURLConnection connection, String httpMethod) {
        try {
            if (!(connection instanceof HttpsURLConnection)) {
                throw new RuntimeException("An instance of HttpsURLConnection is expected");
            }

            HttpsURLConnection httpsConnection = (HttpsURLConnection) connection;

            TrustManager[] trustAllCerts = new TrustManager[]{new X509TrustManager() {
                @Override
                public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                    return null;
                }

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

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

            }
            };
            // 强制使用 TLSv1.2 解决 Received fatal alert: protocol_version; nested exception is javax.net.ssl.SSLException: Received fatal alert: protocol_version 异常情况
            SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
            sslContext.init(null, trustAllCerts, new SecureRandom());
            httpsConnection.setSSLSocketFactory(new MyCustomSSLSocketFactory(sslContext.getSocketFactory()));

            httpsConnection.setHostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String s, SSLSession sslSession) {
                    return true;
                }
            });

            super.prepareConnection(httpsConnection, httpMethod);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * SSLSocketFactory用于创建 SSLSockets
     */
    private class MyCustomSSLSocketFactory extends SSLSocketFactory {

        private final SSLSocketFactory delegate;

        public MyCustomSSLSocketFactory(SSLSocketFactory delegate) {
            this.delegate = delegate;
        }

        // 返回默认启用的密码套件。除非一个列表启用，对SSL连接的握手会使用这些密码套件。
        // 这些默认的服务的最低质量要求保密保护和服务器身份验证
        @Override
        public String[] getDefaultCipherSuites() {
            return delegate.getDefaultCipherSuites();
        }

        // 返回的密码套件可用于SSL连接启用的名字
        @Override
        public String[] getSupportedCipherSuites() {
            return delegate.getSupportedCipherSuites();
        }


        @Override
        public Socket createSocket(final Socket socket, final String host, final int port, final boolean autoClose) throws IOException {
            final Socket underlyingSocket = delegate.createSocket(socket, host, port, autoClose);
            return overrideProtocol(underlyingSocket);
        }


        @Override
        public Socket createSocket(final String host, final int port) throws IOException {
            final Socket underlyingSocket = delegate.createSocket(host, port);
            return overrideProtocol(underlyingSocket);
        }

        @Override
        public Socket createSocket(final String host, final int port, final InetAddress localAddress, final int localPort) throws IOException {
            final Socket underlyingSocket = delegate.createSocket(host, port, localAddress, localPort);
            return overrideProtocol(underlyingSocket);
        }

        @Override
        public Socket createSocket(final InetAddress host, final int port) throws IOException {
            final Socket underlyingSocket = delegate.createSocket(host, port);
            return overrideProtocol(underlyingSocket);
        }

        @Override
        public Socket createSocket(final InetAddress host, final int port, final InetAddress localAddress, final int localPort) throws IOException {
            final Socket underlyingSocket = delegate.createSocket(host, port, localAddress, localPort);
            return overrideProtocol(underlyingSocket);
        }

        private Socket overrideProtocol(final Socket socket) {
            if (!(socket instanceof SSLSocket)) {
                throw new RuntimeException("An instance of SSLSocket is expected");
            }
            // 兼容支持协议版本
            ((SSLSocket) socket).setEnabledProtocols(new String[]{"TLSv1", "TLSv1.1", "TLSv1.2"});
            return socket;
        }
    }
}