1.什么是注册中心
注册中心主要有三种角色：
服务提供者（RPC Server）：在启动时，向 Registry 注册自身服务，并向 Registry 定期发送心跳汇报存活状态。
服务消费者（RPC Client）：在启动时，向 Registry 订阅服务，把 Registry 返回的服务节点列表缓存在本地内存中，并与 RPC Sever 建立连接。
服务注册中心（Registry）：用于保存 RPC Server 的注册信息，当 RPC Server 节点发生变更时，Registry 会同步变更，RPC Client 感知后会刷新本地 内存中缓存的服务节点列表。
2.框架版本
spring boot：2.7.13
spring cloud：2021.0.1
3.xxx-discovery-etcd
支持etcd作为服务的注册中心，在微服务中使用
3.1.使用
pom.xml中引入依赖
<dependency> <groupId>x.xx.xxx</groupId> <artifactId>xxx-discovery-etcd</artifactId> </dependency>
application.yml中配置
spring: application: name: etcd-provider-example xxx: discovery: etcd: server-addr: http://192.168.184.133:2379 instance-name: provider1
启动主类增加注解@EnableDiscoveryClient
4.Spring Cloud和xxx-etcd-discovery的结合
4.1.etcd-provider-demo
pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>org.example</groupId> <artifactId>etcd-provider-demo</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <dependency> <groupId>x.xx.xxx</groupId> <artifactId>xxx-discovery-etcd</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-bootstrap</artifactId> </dependency> </dependencies> </project>
bootstrap.yml
server: port: 18082 spring: application: name: etcd-provider-example xxx: discovery: etcd: server-addr: http://192.168.184.133:2379 instance-name: provider1 logging: level: root: DEBUG io: grpc: netty: NettyClientHandler: INFO org: springframework: boot: autoconfigure: INFO
EtcdProviderExampleApplication
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
@SpringBootApplication
@EnableDiscoveryClient
public class EtcdProviderExampleApplication {
public static void main(String[] args) {
SpringApplication.run(EtcdProviderExampleApplication.class, args);
}
}
EchoController
package x.xx.xxx.etcd.demo;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class EchoController {
@RequestMapping(value = "/echo/{string}", method = RequestMethod.GET)
public String echo(@PathVariable String string) {
return System.currentTimeMillis() + "--Hello Etcd Discovery " + string;
}
}
4.2.etcd-consumer-demo
pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>org.example</groupId> <artifactId>etcd-consumer-demo</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <dependency> <groupId>x.xx.xxx</groupId> <artifactId>xxx-discovery-etcd</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-bootstrap</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-webflux</artifactId> </dependency> </dependencies> </project>
bootstrap.yml
server: port: 18081 spring: application: name: etcd-consumer-example xxx: discovery: etcd: server-addr: http://192.168.184.133:2379 instance-name: consumer1 logging: level: root: DEBUG io: grpc: netty: NettyClientHandler: INFO org: springframework: boot: autoconfigure: INFO
EtcdConsumerExampleApplication
package x.xx.xxx.etcd.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.reactive.function.client.WebClient;
@SpringBootApplication
@EnableDiscoveryClient
public class EtcdConsumerExampleApplication {
public static void main(String[] args) {
SpringApplication.run(EtcdConsumerExampleApplication.class, args);
}
@LoadBalanced
@Bean
public RestTemplate restTemplate() {
return new RestTemplate();
}
@Bean
@LoadBalanced
public WebClient.Builder loadBalancedWebClientBuilder() {
return WebClient.builder();
}
}
TestController
package x.xx.xxx.etcd.demo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.reactive.function.client.WebClient;
@RestController
public class TestController {
private final RestTemplate restTemplate;
@Autowired
public TestController(RestTemplate restTemplate) {this.restTemplate = restTemplate;}
@RequestMapping(value = "/echo/{str}", method = RequestMethod.GET)
public String echo(@PathVariable String str) {
return restTemplate.getForObject("http://etcd-provider-example/echo/" + str, String.class);
}
@Autowired
private WebClient.Builder webClientBuilder;
@RequestMapping(value = "/echo/webClient/{str}", method = RequestMethod.GET)
public String echoWebClient(@PathVariable String str) {
WebClient webClient = webClientBuilder.build();
webClient.get()
.uri("http://etcd-provider-example/echo/" + str)
.retrieve()
.bodyToMono(String.class)
.subscribe(response -> {
System.err.println("控制台响应结果:" + response);
});
return System.currentTimeMillis() + "--echoWebClient--" + str + "--请查看控制台是否执行成功!";
}
}
4.3.启动主程序
EtcdProviderExampleApplication
EtcdConsumerExampleApplication
通过ETCD Manager查看，如下表示注册成功
请求etcd-consumer-demo中接口，查看服务发现功能，更改测试接口，可查看TestController
http://localhost:18081/echo/6666
浏览器返回如下信息表示服务发现成功
1705978409084--Hello Etcd Discovery 6666