如何将SSL MQTT客户端与CA签名的服务器证书连接？

Question

I need to sign up for an MQTT address, but I get an exception. As far as I know, I do not need to upload any certificates, just use the server's. What should I do?

Code:

public void connect() throws MqttException{
    MqttConnectOptions options = new MqttConnectOptions();
    options.setUserName("username");
    options.setPassword("123456".toCharArray());
    options.setAutomaticReconnect(true);

    client = new MqttClient("ssl://myadress:1883", MqttClient.generateClientId());
    client.setCallback(callback);
    System.out.println(topic);
    try {
        client.connect(options);
        client.subscribe(topic);
    } catch (Exception e){
        e.printStackTrace();
    }
}

Exception:

MqttException (0) - javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

I'm using the Eclipse Paho library, and I did not find (or, if I did, I did not understand) anything very enlightening in the library's documentation.

Answer 1

You need to supply your own SSLSocketFactory that has it's own TrustManager that knows to trust your certificate.

You add the SSLSocketFactory to the MqttClientOptions object that gets passed to MqttClient.connect() call.

There are plenty of examples online about settings up a SSLSocketFactory with your own CA certs.