Java tutorial
/** * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. The ASF licenses * this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package net.data.technology.jraft.extensions.http; import java.io.IOException; import java.io.InputStreamReader; import java.nio.charset.StandardCharsets; import java.util.concurrent.CompletableFuture; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpPost; import org.apache.http.concurrent.FutureCallback; import org.apache.http.entity.StringEntity; import org.apache.http.impl.nio.client.CloseableHttpAsyncClient; import org.apache.http.impl.nio.client.HttpAsyncClients; import org.apache.log4j.LogManager; import org.apache.log4j.Logger; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import net.data.technology.jraft.RaftRequestMessage; import net.data.technology.jraft.RaftResponseMessage; import net.data.technology.jraft.RpcClient; public class HttpRpcClient implements RpcClient { private String serverUrl; private CloseableHttpAsyncClient httpClient; private Gson gson; private Logger logger; public HttpRpcClient(String serverUrl) { this.serverUrl = serverUrl; this.httpClient = HttpAsyncClients.createDefault(); this.gson = new GsonBuilder().create(); this.logger = LogManager.getLogger(getClass()); } @Override public CompletableFuture<RaftResponseMessage> send(RaftRequestMessage request) { CompletableFuture<RaftResponseMessage> future = new CompletableFuture<RaftResponseMessage>(); String payload = this.gson.toJson(request); HttpPost postRequest = new HttpPost(this.serverUrl); postRequest.setEntity(new StringEntity(payload, StandardCharsets.UTF_8)); this.httpClient.execute(postRequest, new FutureCallback<HttpResponse>() { @Override public void completed(HttpResponse result) { if (result.getStatusLine().getStatusCode() != 200) { logger.info("receive an response error code " + String.valueOf(result.getStatusLine().getStatusCode()) + " from server"); future.completeExceptionally(new IOException("Service Error")); } try { InputStreamReader reader = new InputStreamReader(result.getEntity().getContent()); RaftResponseMessage response = gson.fromJson(reader, RaftResponseMessage.class); future.complete(response); } catch (Throwable error) { logger.info("fails to parse the response from server due to errors", error); future.completeExceptionally(error); } } @Override public void failed(Exception ex) { future.completeExceptionally(ex); } @Override public void cancelled() { future.completeExceptionally(new IOException("request cancelled")); } }); return future; } }