前一篇講了服務註冊和發現,沒有看過的朋友先看上一篇,這篇是在上一篇基礎上展開。java
Ribbon is a client side load balancer which gives you a lot of control over the behaviour of HTTP and TCP clients. Feign already uses Ribbon, so if you are using @FeignClient then this section also applies.git
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Ribbon是負載均衡客戶端,能夠很好的控制HTTP和TCP客戶端的行爲。 Feign已經集成了Ribbon。spring
Spring Cloud Netflix默認爲ribbon(BeanType beanName:ClassName)提供如下bean:apache
IClientConfig
ribbonClientConfig: DefaultClientConfigImpl
瀏覽器
IRule
ribbonRule: ZoneAvoidanceRule
app
IPing
ribbonPing: NoOpPing
負載均衡
ServerList<Server>
ribbonServerList: ConfigurationBasedServerList
maven
ServerListFilter<Server>
ribbonServerListFilter: ZonePreferenceServerListFilter
ide
ILoadBalancer
ribbonLoadBalancer: ZoneAwareLoadBalancer
這篇文章基於上一篇文章項目,啓動eureka-server
項目;啓動eureka-client
項目,端口爲8040
; 將eureka-client
的配置文件端口改成8041
,並啓動,同一個項目修改端口號,啓動多個實例,只須要在IDEA中勾選Allow parallel run
:
此時你會發現註冊服務中註冊了兩個eureka-client
實例,至關於起了2個節點的集羣。 訪問http://localhost:9090:
使用Spring Initializr
新建一個項目,取名爲ribbon-service
, 在Spring Cloud Discovery中勾選Eureka Discovery Client
,在Spring Cloud Routing中勾選Ribbon
,在Web中勾選Spring Web
:
建立成功後,項目pom.xml以下:
<?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>2.1.9.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.noodles.mars</groupId> <artifactId>ribbon-service</artifactId> <version>0.0.1-SNAPSHOT</version> <name>ribbon-service</name> <description>Ribbon Service</description> <properties> <java.version>1.8</java.version> <spring-cloud.version>Greenwich.SR3</spring-cloud.version> </properties> <dependencies> <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-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </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>
ribbon-service配置服務中心地址、應用名、端口,配置文件內容:
server: port: 8050 spring: application: name: ribbon-service eureka: client: service-url: defaultZone: http://localhost:9090/eureka/
在項目啓動類上註解@EnableDiscoveryClient
, 開啓向服務中心註冊;定義一個 RestTemplate
Bean, 並註解@LoadBalanced
開啓負載均衡功能:
@EnableEurekaClient @SpringBootApplication public class RibbonServiceApplication { public static void main(String[] args) { SpringApplication.run(RibbonServiceApplication.class, args); } @Bean @LoadBalanced public RestTemplate restTemplate() { return new RestTemplate(); } }
寫一個controller, 經過以前定義的RestTemplate
來消費eureka-client
服務的/hello
接口,url
中使用應用名,ribbon
會根據應用名來選擇具體的服務實例,根據服務實例在請求的時候會用具體的url替換掉服務名:
@RestController public class HelloController { private final RestTemplate restTemplate; @Autowired public HelloController(RestTemplate restTemplate) { this.restTemplate = restTemplate; } @GetMapping("/hello") public String hello(@RequestParam("name") String name) { return restTemplate.getForObject("http://HELLO-ERUEKA-CLIENT/hello?name=" + name, String.class); } }
在瀏覽器上屢次訪問 http://localhost:8050/hello?name=Mars :
Hello, My name is Mars, I'm from port: 8040 Hello, My name is Mars, I'm from port: 8041
這說明負載均衡器已經工做了。
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