SpringCloud学习-Spring Cloud Eureka

一、搭建服务注册中心

1.使用idea创建springboot项目

添加依赖

2.修改pom.xml文件

<?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>2.3.0.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.example</groupId><artifactId>eureka</artifactId><version>0.0.1-SNAPSHOT</version><name>eureka</name><description>Demo project for Spring Boot</description><properties><java.version>1.8</java.version><spring-cloud.version>Hoxton.SR5</spring-cloud.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-eureka-server</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>

3.主类添加@EnableEurekaServer注解

通过@EnableEurekaServer注解启动一个服务注册中心提供给其他的应用进行对话

@EnableEurekaServer
@SpringBootApplication
public class EurekaApplication {public static void main(String[] args) {SpringApplication.run(EurekaApplication.class, args);}}

4.配置application.properties文件，添加一下内容

server.port=8761eureka.client.hostname=localhost
# eureka.client.register-with-eureka=false不向注册中心注册自己
eureka.client.register-with-eureka=false
# eureka.client.fetch-registry=false注册中心的职责是维护服务实例，不需要检索服务，所以设置为false
eureka.client.fetch-registry=false
eureka.client.serviceUrl.defaultZone=http://${eureka.client.hostname}:${server.port}/eureka/

5.验证

http://localhost:8761/

二、服务提供搭建

1.创建springboot项目，添加依赖

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 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>2.3.0.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.example</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.SR5</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><!-- 引入log4j2依赖 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-log4j2</artifactId></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>

2.修改application.properties文文件

server.port=8081
spring.application.name=hello-server
eureka.client.service-url.defaultZone=http://localhost:8761/eureka

3.主类添加@EnableDiscoveryClient注解

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

4.通过注入DiscoveryClient对象打印相关内容

@RestController
public class HelloControl {private final Logger logger = Logger.getLogger(String.valueOf(getClass()));@Autowiredprivate DiscoveryClient client; // 服务发现客户端@RequestMapping(value = "/hello", method = RequestMethod.GET)public String test() {System.out.println(client.getServices().get(0));return "hello";}
}

5.查看注册情况

6.访问接口查看服务信息

http://localhost:8081/hello

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三、服务发现与消费

1.创建springboot项目

2. 添加@EnableDiscoveryClient注解让该应用注册为Eureka的客户端应用，以获得服务发现的能力。同时，在主类中创建RestTemplate的SpringBean实例，通过@LoadBalanced注解开启客户端负载均衡。

@EnableDiscoveryClient
@SpringBootApplication
public class RibbonConsumerApplication {@Bean// @LoadBalanced 开启客户端负载均衡@LoadBalancedRestTemplate restTemplate(){return new RestTemplate();}public static void main(String[] args) {SpringApplication.run(RibbonConsumerApplication.class, args);}}

3.创建ConsumerController类实现/ribbon-consumer接口、通过创建RestTemplate来实现对HELLO-SERVER服务提供的test接口进行调用。访问地址是服务名，符合服务治理的要求。

@RestController
public class CustomerController {@AutowiredRestTemplate restTemplate;@RequestMapping(value="/ribbon-consumer",method = RequestMethod.GET)public String helloConsumer(){return restTemplate.getForEntity("http://HELLO-SERVER/hello",String.class).getBody();}
}

4.在application.properties配置Eureka服务注册中心的位置，同时设置消费者的端口为9000,

spring.application.name=ribbon-consumer
server.port=9000eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

5.启动服务后查看eureka，可以看到服务提供方的服务和消费方的服务

6.访问消费者接口测试

http://localhost:9000/ribbon-consumer