public static Upstream selector(final List<Upstream> upstreamList, final String algorithm, final String ip) {
        LoadBalancer loadBalance = ExtensionLoader.getExtensionLoader(LoadBalancer.class).getJoin(algorithm);
        return loadBalance.select(upstreamList, ip);
    }
Selector upstream.

@param upstreamList the upstream list
@param algorithm    the loadBalance algorithm
@param ip           the ip
@return the upstream
shenyu-loadbalancer/src/main/java/org/apache/shenyu/loadbalancer/factory/LoadBalancerFactory.java