How to start selenium browser with proxy

I am trying to start selenium and selenium's browser with proxy but not getting success. I have used two methods:

        Properties sysProps = System.getProperties();
        sysProps.put("proxySet", "true");
        sysProps.put("proxyHost", "190.249.188.220");
        sysProps.put("proxyPort", "81");

and

java -jar lib/selenium-server.jar proxyHost=22.52.50.228 proxyPort=80

but both are not supporting.

is anyone able to help me to start selenium's browser with proxy.