Java 7引入了默认启用的SNI支持。我发现某些错误配置的服务器在SSL握手中发送一个“无法识别的名称”警告，大多数客户端都会忽略这个警告…除了Java。正如bob Kerns提到的，Oracle工程师拒绝“修复”这个bug/特性。

作为解决方案，他们建议设置jsse。enableSNIExtension财产。为了让你的程序在不重新编译的情况下工作，运行你的应用程序:

java -Djsse.enableSNIExtension=false yourClass

该属性也可以在Java代码中设置，但必须在任何SSL操作之前设置。加载SSL库后，您可以更改属性，但它不会对SNI状态产生任何影响。要在运行时禁用SNI(具有上述限制)，请使用:

System.setProperty("jsse.enableSNIExtension", "false");

设置这个标志的缺点是SNI在应用程序中无处不在。为了使用SNI并且仍然支持错误配置的服务器:

Create a SSLSocket with the host name you want to connect to. Let's name this sslsock. Try to run sslsock.startHandshake(). This will block until it is done or throw an exception on error. Whenever an error occurred in startHandshake(), get the exception message. If it equals to handshake alert: unrecognized_name, then you have found a misconfigured server. When you have received the unrecognized_name warning (fatal in Java), retry opening a SSLSocket, but this time without a host name. This effectively disables SNI (after all, the SNI extension is about adding a host name to the ClientHello message).

对于Webscarab SSL代理，此提交实现了回退设置。

我遇到了同样的问题，原来反向dns设置不正确，它指向错误的IP主机名。在我纠正反向dns并重新启动httpd后，警告消失了。 (如果我不纠正反向dns，添加ServerName也为我做了技巧)

Java 7引入了默认启用的SNI支持。我发现某些错误配置的服务器在SSL握手中发送一个“无法识别的名称”警告，大多数客户端都会忽略这个警告…除了Java。正如bob Kerns提到的，Oracle工程师拒绝“修复”这个bug/特性。

作为解决方案，他们建议设置jsse。enableSNIExtension财产。为了让你的程序在不重新编译的情况下工作，运行你的应用程序:

java -Djsse.enableSNIExtension=false yourClass

该属性也可以在Java代码中设置，但必须在任何SSL操作之前设置。加载SSL库后，您可以更改属性，但它不会对SNI状态产生任何影响。要在运行时禁用SNI(具有上述限制)，请使用:

System.setProperty("jsse.enableSNIExtension", "false");

设置这个标志的缺点是SNI在应用程序中无处不在。为了使用SNI并且仍然支持错误配置的服务器:

Create a SSLSocket with the host name you want to connect to. Let's name this sslsock. Try to run sslsock.startHandshake(). This will block until it is done or throw an exception on error. Whenever an error occurred in startHandshake(), get the exception message. If it equals to handshake alert: unrecognized_name, then you have found a misconfigured server. When you have received the unrecognized_name warning (fatal in Java), retry opening a SSLSocket, but this time without a host name. This effectively disables SNI (after all, the SNI extension is about adding a host name to the ClientHello message).

对于Webscarab SSL代理，此提交实现了回退设置。

Use:

System.setProperty(“jsse。enableSNIExtension”、“假”); 重新启动Tomcat(重要)

它应该是有用的。在Apache HttpClient 4.4中重试SNI错误-我们提出的最简单的方法(参见HttpClient -1522):

public class SniHttpClientConnectionOperator extends DefaultHttpClientConnectionOperator {

    public SniHttpClientConnectionOperator(Lookup<ConnectionSocketFactory> socketFactoryRegistry) {
        super(socketFactoryRegistry, null, null);
    }

    @Override
    public void connect(
            final ManagedHttpClientConnection conn,
            final HttpHost host,
            final InetSocketAddress localAddress,
            final int connectTimeout,
            final SocketConfig socketConfig,
            final HttpContext context) throws IOException {
        try {
            super.connect(conn, host, localAddress, connectTimeout, socketConfig, context);
        } catch (SSLProtocolException e) {
            Boolean enableSniValue = (Boolean) context.getAttribute(SniSSLSocketFactory.ENABLE_SNI);
            boolean enableSni = enableSniValue == null || enableSniValue;
            if (enableSni && e.getMessage() != null && e.getMessage().equals("handshake alert:  unrecognized_name")) {
                TimesLoggers.httpworker.warn("Server received saw wrong SNI host, retrying without SNI");
                context.setAttribute(SniSSLSocketFactory.ENABLE_SNI, false);
                super.connect(conn, host, localAddress, connectTimeout, socketConfig, context);
            } else {
                throw e;
            }
        }
    }
}

and

public class SniSSLSocketFactory extends SSLConnectionSocketFactory {

    public static final String ENABLE_SNI = "__enable_sni__";

    /*
     * Implement any constructor you need for your particular application -
     * SSLConnectionSocketFactory has many variants
     */
    public SniSSLSocketFactory(final SSLContext sslContext, final HostnameVerifier verifier) {
        super(sslContext, verifier);
    }

    @Override
    public Socket createLayeredSocket(
            final Socket socket,
            final String target,
            final int port,
            final HttpContext context) throws IOException {
        Boolean enableSniValue = (Boolean) context.getAttribute(ENABLE_SNI);
        boolean enableSni = enableSniValue == null || enableSniValue;
        return super.createLayeredSocket(socket, enableSni ? target : "", port, context);
    }
}

and

cm = new PoolingHttpClientConnectionManager(new SniHttpClientConnectionOperator(socketFactoryRegistry), null, -1, TimeUnit.MILLISECONDS);

我在通过Eclipse访问Ubuntu Linux服务器时遇到了同样的问题。

它表明问题与Apache (re)启动时的警告有关:

[Mon Jun 30 22:27:10 2014] [warn] NameVirtualHost *:80 has no VirtualHosts

... waiting [Mon Jun 30 22:27:11 2014] [warn] NameVirtualHost *:80 has no VirtualHosts

这是由于ports.conf中的一个新条目，其中另一个NameVirtualHost指令与sites-enabled/000-default中的指令一起输入。

在移除ports.conf中的指令后，问题消失了(自然是在重新启动Apache之后)