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简介
EventBus,又称消息总线,类似我们常见的消息中间件。支持点对点、请求与响应、发布订阅模式,支持跨服务跨语言通讯,分布式消息系统。
常见用法
点对点send
消息发送到某个地址上,Vertx把消息分发到注册到这个地址上的某个消费者上,若存在多个消费者,使用轮询算法选择一个消费者接收消息。
Producer
public class Producer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {vertx.setPeriodic(5000L, h -> {System.out.println("***********************");vertx.eventBus().send("test", "你吃了吗");});super.start(startPromise);}
}
Consumer
public class Consumer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {Random random = new Random();int num = random.nextInt(10000);vertx.eventBus().<String>consumer("test", msg -> {System.out.println(String.format("消费者%s接收到消息:%s", num, msg.body()));});super.start(startPromise);}
}
App
public class App {public static void main(String[] args) {Vertx vertx = Vertx.vertx();vertx.deployVerticle(Consumer.class.getName(), new DeploymentOptions().setInstances(3)).compose(res -> vertx.deployVerticle(Producer.class.getName()));}}
AppRunLog
***********************
消费者7414接收到消息:你吃了吗
***********************
消费者6421接收到消息:你吃了吗
***********************
消费者5802接收到消息:你吃了吗
请求响应request
请求与响应也是点对点模式的一种,区别在于消费者可以回复结果,两者可以进行会话交流。
Producer
public class Producer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {vertx.setPeriodic(5000L, h -> {System.out.println("***********************");vertx.eventBus().<String>request("test", "你吃了吗").onComplete(res -> {if (res.succeeded()) {System.out.println("生产者收到回应:"+ res.result().body());}});});super.start(startPromise);}
}
Consumer
public class Consumer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {Random random = new Random();int num = random.nextInt(10000);vertx.eventBus().<String>consumer("test", msg -> {System.out.println(String.format("消费者%s接收到消息:%s", num, msg.body()));msg.reply(num+"吃过啦");});super.start(startPromise);}
}
App
public class App {public static void main(String[] args) {Vertx vertx = Vertx.vertx();vertx.deployVerticle(Consumer.class, new DeploymentOptions().setInstances(3)).compose(res -> vertx.deployVerticle(Producer.class.getName()));}}
AppRunLog
***********************
消费者8585接收到消息:你吃了吗
生产者收到回应:8585吃过啦
***********************
消费者9672接收到消息:你吃了吗
生产者收到回应:9672吃过啦
***********************
消费者3615接收到消息:你吃了吗
生产者收到回应:3615吃过啦
发布订阅publish
消息发送到某个地址上,Vertx把消息分发到注册到这个地址上的所有消费者上。
Producer
public class Producer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {vertx.setPeriodic(5000L, h -> {System.out.println("***********************");vertx.eventBus().publish("test", "你吃了吗");});super.start(startPromise);}
}
Consumer
public class Consumer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {Random random = new Random();int num = random.nextInt(10000);vertx.eventBus().<String>consumer("test", msg -> {System.out.println(String.format("消费者%s接收到消息:%s", num, msg.body()));});super.start(startPromise);}
}
App
public class App {public static void main(String[] args) {Vertx vertx = Vertx.vertx();vertx.deployVerticle(Consumer.class.getName(), new DeploymentOptions().setInstances(3)).compose(res -> vertx.deployVerticle(Producer.class.getName()));}}
AppRunLog
***********************
消费者5195接收到消息:你吃了吗
消费者9192接收到消息:你吃了吗
消费者2572接收到消息:你吃了吗
***********************
消费者2572接收到消息:你吃了吗
消费者5195接收到消息:你吃了吗
消费者9192接收到消息:你吃了吗
编码解码器
Vertx消息总线默认只对一些基础类型的消息提供编码解码,若想要发送一个实体对象消息,那么需要自定义消息编码解码器,不然会报错 No message codec for type.
自定义单个编解码器
User
@Data
public class User {private String id;private String name;
}
UserCodec
public class UserCodec implements MessageCodec<User, User> {/*** 编码* @param buffer* @param user*/@Overridepublic void encodeToWire(Buffer buffer, User user) {Buffer encoded = Json.CODEC.toBuffer(user, false);buffer.appendInt(encoded.length());buffer.appendBuffer(encoded);}/*** 集群传输解码* @param pos* @param buffer* @return*/@Overridepublic User decodeFromWire(int pos, Buffer buffer) {int length = buffer.getInt(pos);pos += 4;Buffer slice = buffer.slice(pos, pos + length);String json = slice.toString();return JacksonUtil.jsonToBean(json, User.class);}/*** 本地传输解码* @param user* @return*/@Overridepublic User transform(User user) {return user;}@Overridepublic String name() {return "user";}@Overridepublic byte systemCodecID() {return -1;}
}
Producer
public class Producer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {vertx.setTimer(2000L, h -> {System.out.println("***********************");User user = new User();user.setId("1");user.setName("张三");vertx.eventBus().<User>request("test", user).onComplete(res -> {if (res.succeeded()) {System.out.println("生产者收到回应:"+ res.result().body());}});});super.start(startPromise);}
}
Consumer
public class Consumer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {vertx.eventBus().<User>consumer("test", msg -> {System.out.println(String.format("消费者接收到消息:%s",msg.body()));User user = new User();user.setId("2");user.setName("李四");msg.reply(user);});super.start(startPromise);}
}
App
public class App {public static void main(String[] args) {Vertx vertx = Vertx.vertx();vertx.eventBus().registerDefaultCodec(User.class, new UserCodec());vertx.deployVerticle(Consumer.class.getName()).compose(res -> vertx.deployVerticle(Producer.class.getName()));}}
AppRunLog
***********************
消费者接收到消息:User(id=1, name=张三)
生产者收到回应:User(id=2, name=李四)
自定义公用编解码器
RestRequest
公用请求参数类
@Data
public class RestRequest<T> {private String reqTopic;private T reqBody;
}
ReqMessageCodec
公用请求参数消息编解码类
public class ReqMessageCodec<T> implements MessageCodec<RestRequest<T>, T> {@Overridepublic void encodeToWire(Buffer buffer, RestRequest<T> request) {Buffer encoded = Json.CODEC.toBuffer(request, false);buffer.appendInt(encoded.length());buffer.appendBuffer(encoded);}@Overridepublic T decodeFromWire(int pos, Buffer buffer) {int length = buffer.getInt(pos);pos += 4;Buffer slice = buffer.slice(pos, pos + length);String s = slice.toString();RestRequest<T> request = JacksonUtil.jsonToBean(s, new TypeReference<>() {});return request.getReqBody();}@Overridepublic T transform(RestRequest<T> request) {return request.getReqBody();}@Overridepublic String name() {return "req";}@Overridepublic byte systemCodecID() {return -1;}
}
RestResponse
公用响应消息类
@Data
public class RestResponse<T> {private int code;private T data;private String msg;
}
RespMessageCodec
公用响应消息编解码类
public class RespMessageCodec<T> implements MessageCodec<RestResponse<T>, RestResponse<T>> {@Overridepublic void encodeToWire(Buffer buffer, RestResponse<T> response) {Buffer encoded = Json.CODEC.toBuffer(response, false);buffer.appendInt(encoded.length());buffer.appendBuffer(encoded);}@Overridepublic RestResponse<T> decodeFromWire(int pos, Buffer buffer) {int length = buffer.getInt(pos);pos += 4;Buffer slice = buffer.slice(pos, pos + length);return JacksonUtil.jsonToBean(slice.toString(), new TypeReference<>() {});}@Overridepublic RestResponse<T> transform(RestResponse<T> response) {return response;}@Overridepublic String name() {return "resp";}@Overridepublic byte systemCodecID() {return -1;}
}
Producer
public class Producer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {vertx.setTimer(2000L, h -> {System.out.println("***********************");User user = new User();user.setId("1");user.setName("张三");RestRequest<User> req = new RestRequest<>();req.setReqTopic("addUser");req.setReqBody(user);vertx.eventBus().<RestResponse>request(req.getReqTopic(), req).onComplete(res -> {if (res.succeeded()) {System.out.println("生产者收到回应:"+ res.result().body());}else {System.out.println("生产者发送消息失败:"+res.cause().getMessage());}});});super.start(startPromise);}
}
Consumer
public class Consumer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {vertx.eventBus().<User>consumer("addUser", msg -> {System.out.println(String.format("消费者接收到消息:%s",msg.body()));RestResponse<String> response = new RestResponse();response.setCode(200);response.setMsg("插入成功");msg.reply(response);});super.start(startPromise);}
}
SingleApp
本地传输数据
public class SingleApp {public static void main(String[] args) {Vertx vertx = Vertx.vertx();vertx.eventBus().registerDefaultCodec(RestRequest.class, new ReqMessageCodec()).registerDefaultCodec(RestResponse.class, new RespMessageCodec());vertx.deployVerticle(Consumer.class.getName()).compose(res -> vertx.deployVerticle(Producer.class.getName()));}}
SingleAppRunLog
***********************
消费者接收到消息:User(id=1, name=张三)
生产者收到回应:RestResponse(code=200, data=null, msg=插入成功)
ClusterApp
集群模式传输数据
public class ClusterApp {static Vertx vertx;public static void initCluster(Verticle service) {ClusterManager mgr = new HazelcastClusterManager();VertxOptions options = new VertxOptions().setClusterManager(mgr);Vertx.clusteredVertx(options).compose(v -> {vertx = v;vertx.eventBus().registerDefaultCodec(RestRequest.class, new ReqMessageCodec()).registerDefaultCodec(RestResponse.class, new RespMessageCodec());return vertx.deployVerticle(service);}).onSuccess(h -> {System.out.println("App Start Complete!");}).onFailure(err -> {err.printStackTrace();System.err.println("App Start Failed "+ err.getMessage());});}
}
ConsumerApp
消费服务
public class ConsumerApp extends ClusterApp{public static void main(String[] args) {initCluster(new Consumer());}
}
ConsumerAppRunLog
Members {size:2, ver:2} [Member [127.0.0.1]:5703 - 29afc653-a4ef-4933-ab6a-ed0bbbb7041e thisMember [127.0.0.1]:5704 - 289a8535-cb6f-4fef-8501-04c40c56f189
]
消费者接收到消息:{id=1, name=张三}
ProducerApp
生产服务
public class ProducerApp extends ClusterApp{public static void main(String[] args) {initCluster(new Producer());}
}
ProducerAppRunLog
Members {size:2, ver:2} [Member [127.0.0.1]:5703 - 29afc653-a4ef-4933-ab6a-ed0bbbb7041eMember [127.0.0.1]:5704 - 289a8535-cb6f-4fef-8501-04c40c56f189 this
]***********************
生产者收到回应:RestResponse(code=200, data=null, msg=插入成功)
DeliveryOptions
设置请求响应超时时间
public class Producer extends AbstractVerticle {@Overridepublic void start(Promise<Void> startPromise) throws Exception {System.out.println(new Date()+"***********************");vertx.eventBus().<String>request("test", "你吃了吗",new DeliveryOptions().setSendTimeout(5000)).onComplete(res -> {if (res.succeeded()) {System.out.println(new Date()+"生产者接收应答消息:"+res.result().body());} else {System.out.println(new Date()+"生产者发送消息失败"+res.cause().getMessage());}});super.start(startPromise);}
}