在上一篇文章,讲了服务的注册和发现。在微服务架构中,业务都会被拆分成一个独立的服务,服务与服务的通讯是基于http restful的。Spring cloud有两种服务调用方式,一种是ribbon+restTemplate,另一种是feign。在这一篇文章首先讲解下基于ribbon+rest。
一、ribbon简介
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.
—–摘自官网
ribbon是一个负载均衡客户端,可以很好的控制htt和tcp的一些行为。Feign默认集成了ribbon。
ribbon 已经默认实现了这些配置bean:
IClientConfig ribbonClientConfig: DefaultClientConfigImpl
IRule ribbonRule: ZoneAvoidanceRule
IPing ribbonPing: NoOpPing
ServerList ribbonServerList: ConfigurationBasedServerList
ServerListFilter ribbonServerListFilter: ZonePreferenceServerListFilter
ILoadBalancer ribbonLoadBalancer: ZoneAwareLoadBalancer
二、开发流程
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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.gui</groupId> <artifactId>springribbon</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>springribbon</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.2.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>9</java.version> <spring-cloud.version>Finchley.BUILD-SNAPSHOT</spring-cloud.version> </properties> <dependencies> <!--pom.xml文件分别引入起步依赖spring-cloud-starter-netflix-eureka-client、spring-cloud-starter-ribbon、spring-boot-starter-web--> <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-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> <repositories> <repository> <id>spring-snapshots</id> <name>Spring Snapshots</name> <url>https://repo.spring.io/snapshot</url> <snapshots> <enabled>true</enabled> </snapshots> </repository> <repository> <id>spring-milestones</id> <name>Spring Milestones</name> <url>https://repo.spring.io/milestone</url> <snapshots> <enabled>false</enabled> </snapshots> </repository> </repositories> </project>
package com.gui.springribbon; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.web.client.RestTemplate; @SpringBootApplication @EnableDiscoveryClient public class SpringribbonApplication { public static void main(String[] args) { SpringApplication.run(SpringribbonApplication.class, args); } @Bean @LoadBalanced RestTemplate restTemplate() { return new RestTemplate(); } }
application.yml
server: port: 8764 eureka: client: service-url: defaultZone: http://localhost:8761/eureka/ spring: application: name: service-ribboncontroller
package com.gui.springribbon.web; import com.gui.springribbon.service.HelloService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; @RestController public class HelloControler { @Autowired HelloService helloService; @RequestMapping(value = "/hi") public String hi(@RequestParam String name){ return helloService.hiService(name); } }
service
package com.gui.springribbon.service; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.web.client.RestTemplate; @Service public class HelloService { @Autowired RestTemplate restTemplate; public String hiService(String name) { return restTemplate.getForObject("http://SERVICE-HI/hi?name="+name,String.class); } }