2.Spring Cloud Eureka客戶端搭建

新建一個工程，名爲eureka-client，pom.xml文件依賴如下：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.2.8.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.hangzhou.springcloud</groupId>
	<artifactId>eureka-client</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>eureka-client</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Hoxton.SR6</spring-cloud.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
			<exclusions>
				<exclusion>
					<groupId>org.junit.vintage</groupId>
					<artifactId>junit-vintage-engine</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>${spring-cloud.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

EurekaClientApplication類代碼如下：

//@EnableDiscoveryClient註解表示是此工程是一個客戶端
@EnableDiscoveryClient
@SpringBootApplication
public class EurekaClientApplication {

	public static void main(String[] args) {
		SpringApplication.run(EurekaClientApplication.class, args);
	}

}

application.properties配置文件如下：

# 指定運行端口號
server.port=1112

# 指定服務名稱
spring.application.name=hello-service
# 註冊到Eureka的註冊中心
eureka.client.register-with-eureka=true
# 獲取註冊實例列表
eureka.client.fetch-registry=true
 # 配置註冊中心地址
eureka.client.service-url.defaultZone=http://localhost:1111/eureka

HelloController類代碼如下：

@RequestMapping(value="/test")
@RestController
public class HelloController {
	
	private final Logger logger = LoggerFactory.getLogger(HelloController.class); 
	
	@Autowired
	private DiscoveryClient discoveryClient;
	
    @RequestMapping(value="hello",method=RequestMethod.GET)
	public String index() {
		List<ServiceInstance> instances = discoveryClient.getInstances("hello-service");
		ServiceInstance serviceInstance = instances.get(0);
		logger.info("/hello,host:"+ serviceInstance.getHost()+",server_id:"+serviceInstance.getPort());
		return "hello word";
	}
}

運行註冊中心的工程，再啓動此工程，打開http://localhost:1111,效果如下：

可以看到有一條註冊信息。話不多說啓動剛纔我們建的hello-service工程，效果如下：