可以使用setRoutePlanner方法来设置路由规划器(RoutePlanner)，并在其中通过HttpHost类来指定请求的主机名、端口和协议。具体实现如下：

import org.apache.http.HttpHost;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.conn.routing.HttpRoutePlanner;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.DefaultProxyRoutePlanner;

public class HttpClient {
    public static void main(String[] args) throws Exception {
        CloseableHttpClient httpClient = null;
        try {
            httpClient = HttpClientBuilder.create().setRoutePlanner(new DefaultProxyRoutePlanner(new HttpHost("myproxy", 8080) {
                @Override
                public String getSchemeName() {
                    return "http";
                }

                @Override
                public String getHostName() {
                    return "myhost";
                }

                @Override
                public int getPort() {
                    return 80;
                }
            })).build();
            HttpRoutePlanner routePlanner = httpClient.getRoutePlanner();
            HttpRoute route = routePlanner.determineRoute(new HttpHost("myhost", 80), null, null);
            System.out.println(route.getTargetHost().getHostName() + " " + route.getTargetHost().getPort() + " " + route.getProxyHost());
        } finally {
            if (httpClient != null) {
                httpClient.close();
            }
        }
    }
}

在代码中，我们使用setRoutePlanner方法设置了路由规划器(DefaultProxyRoutePlanner)，并在其中使用HttpHost类来指定请求的主机名、端口和协议。最后使用getRoutePlanner来获取路由规划器，并使用determineRoute方法获取当前的路由规划。