使用Apache Curator实现服务的注册和发现

使用zookeeper可以实现服务的注册和发现，而Curator是对zookeeper进行的一层封装，自然也封装了一套实现服务的注册和发现，本文就介绍如何使用Curator实现服务的注册和发现

首先要安装zookeeper，我这里安装的是：zookeeper-3.4.6

curator 的依赖版本如下：

<dependency><groupId>org.apache.curator</groupId><artifactId>curator-x-discovery-server</artifactId><version>2.9.1</version></dependency>

做服务的注册和发现，自然要有服务端和客户端

服务端代码如下：

服务端一：

package com.mall.zk.service;/** * 服务的附加信息 */public class ServiceDetail {//服务注册的根路径public static final String REGISTER_ROOT_PATH = "/mall";private String desc;private int weight;public ServiceDetail() {}public ServiceDetail(String desc, int weight) {this.desc = desc;this.weight = weight;}public String getDesc() {return desc;}public void setDesc(String desc) {this.desc = desc;}public int getWeight() {return weight;}public void setWeight(int weight) {this.weight = weight;}@Overridepublic String toString() {return "ServiceDetail [desc=" + desc + ", weight=" + weight + "]";}}

package com.mall.zk.server;import java.util.concurrent.TimeUnit;import org.apache.curator.framework.CuratorFramework;import org.apache.curator.framework.CuratorFrameworkFactory;import org.apache.curator.retry.ExponentialBackoffRetry;import org.apache.curator.x.discovery.ServiceDiscovery;import org.apache.curator.x.discovery.ServiceDiscoveryBuilder;import org.apache.curator.x.discovery.ServiceInstance;import org.apache.curator.x.discovery.ServiceInstanceBuilder;import org.apache.curator.x.discovery.details.JsonInstanceSerializer;import com.mall.zk.service.ServiceDetail;public class AppServer {public static void main(String[] args) throws Exception {CuratorFramework client = CuratorFrameworkFactory.newClient("192.168.1.101:2181", new ExponentialBackoffRetry(1000, 3));client.start();client.blockUntilConnected();/** * 指定服务的 地址，端口，名称 */ServiceInstanceBuilder<ServiceDetail> sib = ServiceInstance.builder();sib.address("192.168.1.100");sib.port(8855);sib.name("tomcat");sib.payload(new ServiceDetail("主站web程序", 1));ServiceInstance<ServiceDetail> instance = sib.build();ServiceDiscovery<ServiceDetail> serviceDiscovery = ServiceDiscoveryBuilder.builder(ServiceDetail.class)   .client(client)   .serializer(new JsonInstanceSerializer<ServiceDetail>(ServiceDetail.class))   .basePath(ServiceDetail.REGISTER_ROOT_PATH)   .build();//服务注册serviceDiscovery.registerService(instance);serviceDiscovery.start();TimeUnit.SECONDS.sleep(70);serviceDiscovery.close();client.close();}}

服务端二：

package com.mall.zk.server;import java.util.concurrent.TimeUnit;import org.apache.curator.framework.CuratorFramework;import org.apache.curator.framework.CuratorFrameworkFactory;import org.apache.curator.retry.ExponentialBackoffRetry;import org.apache.curator.x.discovery.ServiceDiscovery;import org.apache.curator.x.discovery.ServiceDiscoveryBuilder;import org.apache.curator.x.discovery.ServiceInstance;import org.apache.curator.x.discovery.ServiceInstanceBuilder;import org.apache.curator.x.discovery.details.JsonInstanceSerializer;import com.mall.zk.service.ServiceDetail;public class AppServer2 {public static void main(String[] args) throws Exception {CuratorFramework client = CuratorFrameworkFactory.newClient("192.168.1.101:2181", new ExponentialBackoffRetry(1000, 3));client.start();client.blockUntilConnected();/** * 指定服务的 地址，端口，名称 */ServiceInstanceBuilder<ServiceDetail> sib = ServiceInstance.builder();sib.address("192.168.1.100");sib.port(8866);sib.name("tomcat");sib.payload(new ServiceDetail("主站web程序", 2));ServiceInstance<ServiceDetail> instance = sib.build();ServiceDiscovery<ServiceDetail> serviceDiscovery = ServiceDiscoveryBuilder.builder(ServiceDetail.class)   .client(client)   .serializer(new JsonInstanceSerializer<ServiceDetail>(ServiceDetail.class))   .basePath(ServiceDetail.REGISTER_ROOT_PATH)   .build();//服务注册serviceDiscovery.registerService(instance);serviceDiscovery.start();TimeUnit.SECONDS.sleep(70);serviceDiscovery.close();client.close();}}

上面两个服务端代码，几乎一样，只是服务端口，权重不一样。然后运行上面两个main方法

然后，去zk里面查看

[zk: localhost:2181(CONNECTED) 54] ls /mall/tomcat
[a8657594-ef32-4efc-b2b0-3077d105e486, b5b55bbc-ce04-4b70-9413-1ec3c54023b8]
可以看到，有2个临时节点，也就意味着有两个服务

客户端代码：

package com.mall.zk.client;import java.util.Collection;import org.apache.curator.framework.CuratorFramework;import org.apache.curator.framework.CuratorFrameworkFactory;import org.apache.curator.retry.ExponentialBackoffRetry;import org.apache.curator.x.discovery.ServiceDiscovery;import org.apache.curator.x.discovery.ServiceDiscoveryBuilder;import org.apache.curator.x.discovery.ServiceInstance;import com.mall.zk.service.ServiceDetail;public class AppClient {public static void main(String[] args) throws Exception{CuratorFramework client = CuratorFrameworkFactory.newClient("192.168.1.101:2181", new ExponentialBackoffRetry(1000, 3));client.start();client.blockUntilConnected();ServiceDiscovery<ServiceDetail> serviceDiscovery = ServiceDiscoveryBuilder.builder(ServiceDetail.class).client(client).basePath(ServiceDetail.REGISTER_ROOT_PATH).build();serviceDiscovery.start();//根据名称获取服务Collection<ServiceInstance<ServiceDetail>> services = serviceDiscovery.queryForInstances("tomcat");for(ServiceInstance<ServiceDetail> service : services) {System.out.println(service.getPayload());System.out.println(service.getAddress() + "\t" + service.getPort());System.out.println("---------------------");}serviceDiscovery.close();client.close();}}

运行客户端，输出：

ServiceDetail [desc=主站web程序, weight=2]192.168.1.1008866---------------------ServiceDetail [desc=主站web程序, weight=1]192.168.1.1008855---------------------