如何配置Apache作为HTTPS tomcat7后端的反向代理?

我已将tomcat7配置为在端口8443上成功使用letencrypt SSL。 现在我只想接受443端口,我在它前面使用apache2。 我添加了虚拟主机,这是ubuntu /etc/apache2/av​​ailable-site/example.com.conf上的内容:

ServerName example.com
ServerAlias *.example.com
ProxyPreserveHost on
ProxyRequests off

      <Proxy *>
              Order deny,allow
              Allow from all
       </Proxy>

SSLEngine on
SSLProxyEngine on
SSLVerifyClient None
SSLCertificateFile    /etc/letsencrypt/live/example.com/cert.pem
SSLCertificateKeyFile /etc/letsencrypt/live/example.com/privkey.pem
SSLCertificateChainFile /etc/letsencrypt/live/example.com/fullchain.pem



ProxyPass / https://localhost:8443/
ProxyPassReverse / https://localhost:8443/
RequestHeader set X-Forwarded-Proto "https"
RequestHeader set X-Forwarded-Port "443"

这是与SSL相关的tomcat 7 server.xml的内容:

<Connector executor="tomcatThreadPool"
            port="8080" protocol="HTTP/1.1"
            connectionTimeout="20000"
            redirectPort="8443" />


<Connector
           protocol="org.apache.coyote.http11.Http11NioProtocol"
           port="8443" maxThreads="200"
           scheme="https" secure="true" SSLEnabled="true" keystoreType="PKCS12"
           keystoreFile="/home/ubuntu/example.jks" keystorePass="example"
           clientAuth="false" sslProtocol="TLS"/>

当我尝试使用elinks连接时:

$ elinks https://localhost

我收到此消息:

503 proxy Error the proxy server received an invalid response from an upstream server.

还应该为Apache还是tomcat 7配置证书位置。 任何帮助!