高端品牌网站设计欣赏,网站做404好处,wordpress 被攻击,网站 色彩了解proto3后,接下来看官方Demo作为训练,这里建议看一遍之后自己动手搭建出来,一方面巩固之前的知识,一方面是对整个流程更加熟悉.官方Demo地址: https://github.com/grpc/grpc-java例子是一个简单的路由映射的应用#xff0c;它允许客户端获取路由特性的信息#xff0c;生成…了解proto3后,接下来看官方Demo作为训练,这里建议看一遍之后自己动手搭建出来,一方面巩固之前的知识,一方面是对整个流程更加熟悉.官方Demo地址: https://github.com/grpc/grpc-java例子是一个简单的路由映射的应用它允许客户端获取路由特性的信息生成路由的总结以及交互路由信息如服务器和其他客户端的流量更新.1.1定义服务也就是写proto文件//指定proto3格式syntax proto3;//一些生成代码的设置option java_multiple_files true;//以外部类模式生成option java_package cn.mrdear.route;//所在包名option java_outer_classname RouteProto;//最外层类名称//定义服务service RouteGuide{//得到指定点的feature//一个 简单 RPC 客户端使用存根发送请求到服务器并等待响应返回就像平常的函数调用一样。rpc GetFeature(Point) returns (Feature) {}//获取一个矩形内的点//一个 服务器端流式 RPC 客户端发送请求到服务器拿到一个流去读取返回的消息序列。 客户端读取返回的流//直到里面没有任何消息。从例子中可以看出通过在 响应 类型前插入 stream 关键字可以指定一个服务器端的流方法。rpc ListFeatures(Rectangle) returns (stream Feature){}//记录该点//一个 客户端流式 RPC 客户端写入一个消息序列并将其发送到服务器同样也是使用流。一旦客户端完成写入消息//它等待服务器完成读取返回它的响应。通过在 请求 类型前指定 stream 关键字来指定一个客户端的流方法。rpc RecordRoute(stream Point) returns (RouteSummary){}//路由交流//一个 双向流式 RPC 是双方使用读写流去发送一个消息序列。两个流独立操作因此客户端和服务器//可以以任意喜欢的顺序读写比如 服务器可以在写入响应前等待接收所有的客户端消息或者可以交替 的读取和写入消息//或者其他读写的组合。每个流中的消息顺序被预留。你可以通过在请求和响应前加 stream 关键字去制定方法的类型。rpc RouteChat(stream RouteNote) returns (stream RouteNote){}}//代表经纬度message Point {int32 latitude 1;int32 longitude 2;}//由两个点确定的一个方块message Rectangle{Point lo 1;Point hi 2;}//某一位置的名称message Feature {string name 1;Point location 2;}// Not used in the RPC. Instead, this is here for the form serialized to disk.message FeatureDatabase {repeated Feature feature 1;}//给某一点发送消息message RouteNote{Point location 1;string message 2;}//记录收到的信息message RouteSummary{int32 point_count 1;int32 feture_count 2;int32 distance 3;int32 elapsed_time 4;}执行mvn compile生成如下代码:1.2编写RouteGuideService该类就是这个项目所提供给外部的功能.该类需要继承RouteGuideGrpc.RouteGuideImplBase,这个类提供了我们所定义分服务接口,继承后覆盖需要实现的自定义方法.简单 RPC简单RPC和普通方法调用形式差不多,客户端传来一个实体,服务端返回一个实体.Overridepublic void getFeature(Point request, StreamObserver responseObserver) {System.out.println(getFeature得到的请求参数: request.toString());// responseObserver.onError(); 代表请求出错responseObserver.onNext(checkFeature(request));//包装返回信息responseObserver.onCompleted();//结束一次请求}//找到复核的featureprivate Feature checkFeature(Point location) {for (Feature feature : features) {if (feature.getLocation().getLatitude() location.getLatitude() feature.getLocation().getLongitude() location.getLongitude()) {return feature;}}// No feature was found, return an unnamed feature.return Feature.newBuilder().setName().setLocation(location).build();}其中StreamObserver是一个应答观察者,用于封装返回的信息,服务器把该信息传给客户端.请求结束要调用onCompleted()方法.服务器端流式 RPC在proto文件中声明了stream,但是从接口上看不出来和简单RPC的区别,代码中最主要的区别是多次调用responseObserver.onNext()的方法,最后完成时写回数据.Overridepublic void listFeatures(Rectangle request, StreamObserver responseObserver) {int left min(request.getLo().getLongitude(), request.getHi().getLongitude());int right max(request.getLo().getLongitude(), request.getHi().getLongitude());int top max(request.getLo().getLatitude(), request.getHi().getLatitude());int bottom min(request.getLo().getLatitude(), request.getHi().getLatitude());for (Feature feature : features) {//如果不存在则继续if (!RouteGuideUtil.exists(feature)) {continue;}int lat feature.getLocation().getLatitude();int lon feature.getLocation().getLongitude();if (lon left lon right lat bottom lat top) {//找到符合的就写入responseObserver.onNext(feature);}}//最后标识完成responseObserver.onCompleted();}客户端流式 RPC服务端就需要一直监控客户端写入情况,因此需要一个StreamObserver接口,其中onNext方法会在客户端每次写入时调用,当写入完毕时调用onCompleted()方法.具体还要到后面客户端调用分析.Overridepublic StreamObserver recordRoute(StreamObserver responseObserver) {return new StreamObserver() {int pointCount;int featureCount;int distance;Point previous;long startTime System.nanoTime();//客户端每写入一个Point,服务端就会调用该方法Overridepublic void onNext(Point point) {System.out.println(recordRoute得到的请求参数: point.toString());pointCount;if (RouteGuideUtil.exists(checkFeature(point))) {featureCount;}if (previous ! null) {distance calcDistance(previous, point);}previous point;}Overridepublic void onError(Throwable throwable) {throwable.printStackTrace();System.err.println(Encountered error in recordRoute);}//客户端写入结束时调用Overridepublic void onCompleted() {long seconds NANOSECONDS.toSeconds(System.nanoTime() - startTime);responseObserver.onNext(RouteSummary.newBuilder().setPointCount(pointCount).setFetureCount(featureCount).setDistance(distance).setElapsedTime((int) seconds).build());responseObserver.onCompleted();}};}双向流式 RPC和客户端流式RPC差不多.Overridepublic StreamObserver routeChat(StreamObserver responseObserver) {return new StreamObserver() {Overridepublic void onNext(RouteNote note) {List notes getOrCreateNotes(note.getLocation());for (RouteNote prevNote : notes.toArray(new RouteNote[0])) {responseObserver.onNext(prevNote);}notes.add(note);}Overridepublic void onError(Throwable t) {t.printStackTrace();System.err.println(Encountered error in routeChat);}Overridepublic void onCompleted() {responseObserver.onCompleted();}};}1.3创建服务端和Helloworld一样的形式,最主要的是addService(new RouteGuideService(features)),这里把需要注册的服务给注册上.public class RouteGuideServer {private final int port;//服务端端口private final Server server;//服务器public RouteGuideServer(int port) throws IOException {this.port port;//获取初始化数据List features RouteGuideUtil.parseFeatures(RouteGuideUtil.getDefaultFeaturesFile());//初始化Server参数server ServerBuilder.forPort(port)//添加指定服务.addService(new RouteGuideService(features)).build();}/*** 启动服务*/public void start() throws IOException {server.start();System.out.println(Server started, listening on port);//程序退出时关闭资源Runtime.getRuntime().addShutdownHook(new Thread(() - {System.err.println(*** shutting down gRPC server since JVM is shutting down);RouteGuideServer.this.stop();System.err.println(*** server shut down);}));}/*** 关闭服务*/public void stop() {if (server ! null) {server.shutdown();}}/*** 使得server一直处于运行状态*/private void blockUntilShutdown() throws InterruptedException {if (server ! null) {server.awaitTermination();}}public static void main(String[] args) throws IOException, InterruptedException {RouteGuideServer server new RouteGuideServer(50051);server.start();server.blockUntilShutdown();}}1.4编写客户端客户端需要一个channel和一个存根blockingStub或者asyncStub根据业务需要选择同步或者异步.private final ManagedChannel channel;//grpc信道,需要指定端口和地址private final RouteGuideGrpc.RouteGuideBlockingStub blockingStub;//阻塞/同步存根private final RouteGuideGrpc.RouteGuideStub asyncStub;//非阻塞,异步存根public RouteGuideClient(String host,int port) {//创建信道channel ManagedChannelBuilder.forAddress(host, port).usePlaintext(true).build();//创建存根blockingStub RouteGuideGrpc.newBlockingStub(channel);asyncStub RouteGuideGrpc.newStub(channel);}/*** 关闭方法*/public void shutdown() throws InterruptedException {channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);}简单grpc和调用普通方法形式差不多.public void getFeature(int lat,int lon){System.out.println(start getFeature);Point request Point.newBuilder().setLatitude(lat).setLongitude(lon).build();Feature feature;try {//同步阻塞调用feature blockingStub.getFeature(request);System.out.println(getFeature服务端返回 : feature);} catch (StatusRuntimeException e) {System.out.println(RPC failed e.getStatus());}}调用代码:public static void main(String[] args) throws InterruptedException {RouteGuideClient client new RouteGuideClient(localhost, 50051);try {client.getFeature(409146138, -746188906);//成功案例client.getFeature(0, 0);//失败案例} finally {client.shutdown();}}客户端日志服务端日志(参数都为0的时候,这边并没拿到参数)服务器端流式 RPC和简单RPC差不多,只不过返回的是一个集合类.//2.服务端流式RPCpublic void listFeatures(int lowLat, int lowLon, int hiLat, int hiLon){System.out.println(start listFeatures);Rectangle request Rectangle.newBuilder().setLo(Point.newBuilder().setLatitude(lowLat).setLongitude(lowLon).build()).setHi(Point.newBuilder().setLatitude(hiLat).setLongitude(hiLon).build()).build();Iterator features;try {features blockingStub.listFeatures(request);for (int i 1; features.hasNext(); i) {Feature feature features.next();System.out.println(getFeature服务端返回 : feature);}} catch (Exception e) {System.out.println(RPC failed e.getMessage());}}客户端日志:服务端日志:客户端流式 RPC该种方式两遍都是异步操作,所以需要互相监听,也因此需要使用阻塞存根.服务端监听Point的写入,客户端监听RouteSummary的写回.public void recordRoute(List features, int numPoints) throws InterruptedException {System.out.println(start recordRoute);final CountDownLatch finishLatch new CountDownLatch(1);//建一个应答者接受返回数据StreamObserver responseObserver new StreamObserver() {Overridepublic void onNext(RouteSummary summary) {System.out.println(recordRoute服务端返回 : summary);}Overridepublic void onError(Throwable t) {System.out.println(RecordRoute Failed);finishLatch.countDown();}Overridepublic void onCompleted() {System.out.println(RecordRoute finish);finishLatch.countDown();}};//客户端写入操作StreamObserver requestObserver asyncStub.recordRoute(responseObserver);Random random new Random();try {for (int i 0; i numPoints; i) {int index random.nextInt(features.size());Point point features.get(index).getLocation();System.out.println(客户端写入point: point);requestObserver.onNext(point);Thread.sleep(random.nextInt(1000) 500);if (finishLatch.getCount() 0) {return;}}} catch (RuntimeException e) {requestObserver.onError(e);throw e;}//标识已经写完requestObserver.onCompleted();// Receiving happens asynchronouslyif (!finishLatch.await(1, TimeUnit.MINUTES)) {System.out.println(recordRoute can not finish within 1 minutes);}}客户端日志:服务端日志:双向流式 RPC和客户端流式RPC比较接近,同样都需要双方监控.public CountDownLatch routeChat() {System.out.println(start routeChat);final CountDownLatch finishLatch new CountDownLatch(1);//写入监听StreamObserver requestObserver //写回监听asyncStub.routeChat(new StreamObserver() {//服务端每写回一个操作就调用Overridepublic void onNext(RouteNote note) {System.out.println(服务端写回: note);}Overridepublic void onError(Throwable t) {t.printStackTrace();System.out.println(RouteChat Failed:);finishLatch.countDown();}Overridepublic void onCompleted() {System.out.println(Finished RouteChat);finishLatch.countDown();}});try {RouteNote[] requests {newNote(First message, 0, 0), newNote(Second message, 0, 1),newNote(Third message, 1, 0), newNote(Fourth message, 1, 1)};for (RouteNote request : requests) {System.out.println(客户端写入: request);requestObserver.onNext(request);}} catch (RuntimeException e) {requestObserver.onError(e);throw e;}//标识写完requestObserver.onCompleted();return finishLatch;}这里调用需要特殊处理下;CountDownLatch finishLatch client.routeChat();if (!finishLatch.await(1, TimeUnit.MINUTES)) {System.out.println(routeChat can not finish within 1 minutes);}客户端日志:服务端日志:官方Demo之后,入门算结束,接下来就要看详细的官方文档,然后在项目中使用,这个过程会遇到不少问题,解决这些问题就是对这个技术的熟练.附录:
