Spring Cloud - Ribbon負載均衡

一.前言

在Spring Cloud - Ribbon的真情獨白中,我們已經給他們介紹了ribbon。今天我們通過一個小案例，來簡單入門ribbon;

在今天的案例中,我們啓動三個服務提供方,結合ribbon,來看看具體的負載均衡效果。

二.創建項目

經過上面一頓騷操作,我們的模塊就成功創建了[controller和service後來創建];

三.配置項目

3.1 springcloud-ribbon

3.1.1 添加@EnableDiscoveryClient

@SpringBootApplication
@EnableDiscoveryClient
public class ServiceProviderApplication {

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

}

3.1.2 pom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>com.milo</groupId>
		<artifactId>milgenius-springcloud</artifactId>
		<version>1.0.0</version>
	</parent>
	<groupId>com.milo</groupId>
	<artifactId>springcloud-ribbon</artifactId>
	<version>1.0.0</version>
	<name>springcloud-ribbon</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.SR1</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.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-ribbon</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>

3.1.3 application.yml

eureka:
  client:
  serviceUrl:
    defaultZone: http://localhost:8761/eureka/

server:
  port: 8768

spring:
  application:
    name: service-ribbon

3.1.4 相關代碼

ConsumerController:

/**
 * @author: Milogenius
 * @create: 2019-06-28 13:45
 * @description:
 **/
@RestController
public class ConsumerController {

    @Autowired
    private IConsumerService consumerService;

    @RequestMapping(value = "/hello",method = RequestMethod.GET)
    public String index(@RequestParam String name){
        return  consumerService.hello(name);
    }
}

IConsumerService:

/**
 * @author: Milogenius
 * @create: 2019-06-28 13:48
 * @description:
 **/
public interface IConsumerService {

    String hello(String name);
}

ConsumerServiceImpl:

/**
 * @author: Milogenius
 * @create: 2019-06-28 13:49
 * @description:
 **/
@Service
public class ConsumerServiceImpl implements IConsumerService {

    @Autowired
    RestTemplate restTemplate;
    @Override
    public String hello(String name) {
        return restTemplate.getForObject("http://SERVICE-PROVIDER:8762/hello?name="+name,String.class);
    }
}

3.2 springcloud-service-provider

本次測試的服務提供方,我們還是使用Spring Cloud - Eureka Client文中提到的springcloud-service-provider模塊,但是我們需要做一些修改。

ProviderController:

/**
 * @author: Milogenius
 * @create: 2019-06-28 12:14
 * @description:
 **/
@RestController
@Slf4j
public class ProviderController {

    //變動的地方
    @Value("${server.port}")
    private String port;

    @Autowired
    private DiscoveryClient client;

    @RequestMapping(value = "/hello",method = RequestMethod.GET)
    public String index(){
        log.info("hello");
        //響應時候帶着端口號,可以看到從那臺服務器響應的內容
        return "hello world from Port:"+port;
    }
}

四.案例測試

首先,我們啓動註冊中心springcloud-eureka-server

接着,我們啓動springcloud-ribbon

下面,我們啓動三個服務,在啓動之前,需要閱讀如何在IntelliJ Idea中同時啓動不同端口的兩個實例

如上圖所示,依次修改端口號啓動三個服務;

至此,我們項目啓動完成;

接下來,我們測試一下客戶端負載均衡:

通過上面的圖片,我們可以看到請求負載到了我們的三個服務,實現了我們開頭中提到的目標;

示例代碼

milogenius-springcloud