Eureka 注册服务及 Ribbon 负载均衡

Aug 2, 2019

EurekaServer

pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
    <relativePath/>
</parent>

<properties>
    <java.version>1.8</java.version>
    <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
</properties>

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

application.properties

server.port=8765
eureka.instance.hostname=localhost
# 是否将自己注册到EurekaServer上，默认为true。由于当前应用就是EurekaServer，所以置为false
eureka.client.register-with-eureka=false
# 是否从EurekaServer获取注册信息，默认为true。单节点不需要同步其他EurekaServer节点数据，所以置为false
eureka.client.fetch-registry=false
eureka.client.serviceUrl.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/

启动类

@EnableEurekaServer
@SpringBootApplication
public class EurekaServer {

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

EurekaClient

pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
    <relativePath/>
</parent>

<properties>
    <java.version>1.8</java.version>
    <spring-cloud.version>Greenwich.SR2</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>
</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>

application.properties

server.port=8760
spring.application.name=helloworld
eureka.client.serviceUrl.defaultZone=http://localhost:8765/eureka/

启动类

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

Controller

@RestController
public class TestController {

    @Value("${server.port}")
    String port;

    @RequestMapping("/hello")
    public String hello(String name) {
        return port + " says:hello " + name;
    }
}

EurekaClient 需要至少两个才能看出 Ribbon 的负载均衡效果，所以将端口变一下启动两个 EurekaClient

Ribbon

pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
    <relativePath/>
</parent>

<properties>
    <java.version>1.8</java.version>
    <spring-cloud.version>Greenwich.SR2</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>
</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>

application.yml

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8765/eureka/
server:
  port: 8766
spring:
  application:
    name: ribbon

Ribbon

@EnableDiscoveryClient
@SpringBootApplication
public class Ribbon {

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

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }
}

Service

@Service
public class TestService {

    @Autowired
    RestTemplate restTemplate;

    public String hello(String name) {
        return restTemplate.getForObject("http://helloworld/hello?name=" + name, String.class);
    }
}

Controller

@RestController
public class TestController {

    @Autowired
    private TestService testService;

    @RequestMapping("/hello")
    public String hello(@RequestParam String name) {
        return testService.hello(name);
    }
}

服务全部启动后，连续刷新 http://localhost:8766/hello?name=world 即可看到负载均衡效果