SpringCloud——Ribbon从0到1入门实战
Ribbon
Ribbon是Netflix发布的负载均衡器，它有助于控制HTTP和TCP客户端的行为。为Ribbon配置服务提供者地址列表后，Ribbon就可基于某种负载均衡算法，自动地帮助服务消费者去请求。Ribbon默认为我们提供了很多的负载均衡算法，例如轮询、随机等。当然，我们也可为Ribbon实现自定义的负载均衡算法。
在Spring Cloud中，当Ribbon与Eureka配合使用时，Ribbon可自动从Eureka Server获取服务提供者地址列表，并基于负载均衡算法，请求其中一个服务提供者实例。图5-1展示了Ribbon与Eureka配合使用时的大致架构。
创建Eureka注册中心
- pom.xml
<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>4.0.0modelVersion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.2.2.RELEASEversion>
<relativePath/>
parent>
<groupId>com.lanhgroupId>
<artifactId>eurekaartifactId>
<version>0.0.1-SNAPSHOTversion>
<name>eurekaname>
<description>Demo project for Spring Bootdescription>
<properties>
<java.version>1.8java.version>
properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>Hoxton.SR1version>
<type>pomtype>
<scope>importscope>
dependency>
dependencies>
dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-serverartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starterartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
- application.yml
server:
# 设置 Eureka Server WEB 控制台端口、服务注册发现端口。Eureka Server 服务注册 发现端口默认为 8761。
port: 8761
spring:
application:
# 设置 spring 应用命名，默认为 null。同命名的应用会注册到同一个服务集群中。
name: cloud-eureka
eureka:
client:
# 是否将自己注册到 Eureka-Server 中，默认的为 true
register-with-eureka: false
# 是否从 Eureka-Server 中获取服务注册信息，默认为 true
fetch-registry: false
service-url:
defaultZone: http://localhost:8761/eureka/
- 启动类
package com.lanh.eureka;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaApplication.class, args);
}
}
创建服务提供者
- pom.xml文件
<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>4.0.0modelVersion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.2.2.RELEASEversion>
<relativePath/>
parent>
<groupId>com.lanhgroupId>
<artifactId>provider-userartifactId>
<version>0.0.1-SNAPSHOTversion>
<name>provider-username>
<description>Demo project for Spring Bootdescription>
<properties>
<java.version>1.8java.version>
properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>Hoxton.SR1version>
<type>pomtype>
<scope>importscope>
dependency>
dependencies>
dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starterartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
<dependency>
<groupId>org.junit.jupitergroupId>
<artifactId>junit-jupiter-apiartifactId>
<version>5.8.2version>
<scope>testscope>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
- application.yml
server:
# 设置 Eureka Server WEB 控制台端口、服务注册发现端口。Eureka Server 服务注册 发现端口默认为 8761。
port: 8081
spring:
application:
# 设置 spring 应用命名，默认为 null。同命名的应用会注册到同一个服务集群中。
name: provider-user
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/
instance:
prefer-ip-address: true
- 提供服务
package com.lanh.provideruser.controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* @Author Lanh
**/
@RestController
public class Controller {
@GetMapping("/show")
public String show(){
return "Hello";
}
}
- 启动类
package com.lanh.provideruser;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@SpringBootApplication
@EnableEurekaClient
public class ProviderUserApplication {
public static void main(String[] args) {
SpringApplication.run(ProviderUserApplication.class, args);
}
}
服务消费者
- pom.xml
<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>4.0.0modelVersion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.2.2.RELEASEversion>
<relativePath/>
parent>
<groupId>com.lanhgroupId>
<artifactId>ribbonartifactId>
<version>0.0.1-SNAPSHOTversion>
<name>ribbonname>
<description>Demo project for Spring Bootdescription>
<properties>
<java.version>1.8java.version>
properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>Hoxton.SR1version>
<type>pomtype>
<scope>importscope>
dependency>
dependencies>
dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starterartifactId>
dependency>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-serverartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
- application.yml
server:
# 设置 Eureka Server WEB 控制台端口、服务注册发现端口。Eureka Server 服务注册 发现端口默认为 8761。
port: 8083
spring:
application:
# 设置 spring 应用命名，默认为 null。同命名的应用会注册到同一个服务集群中。
name: consumer
eureka:
client:
# 是否将自己注册到 Eureka-Server 中，默认的为 true
register-with-eureka: false
service-url:
defaultZone: http://localhost:8761/eureka/
instance:
prefer-ip-address: true
- 调用服务
package com.lanh.ribbon.controller;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
/**
* @Author Lanh
**/
@RestController
public class Controller {
private static final Logger LOGGER = LoggerFactory.getLogger(Controller.class);
@Autowired
private RestTemplate restTemplate;
@Autowired
private LoadBalancerClient loadBalancerClient;
@GetMapping("/show/{name}")
public String show(@PathVariable String name){
return this.restTemplate.getForObject("http://provider-user/show",String.class)+" "+name;
}
@GetMapping("log-user-instance")
public void logUserInstance(){
ServiceInstance serviceInstance = this.loadBalancerClient.choose("provider-user");
Controller.LOGGER.info("{}:{}:{}",serviceInstance.getInstanceId(),serviceInstance.getHost(),serviceInstance.getPort());
}
}
- 启动类
package com.lanh.ribbon;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
@EnableEurekaClient
public class RibbonApplication {
@Bean
@LoadBalanced
public RestTemplate restTemplate(){
return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(RibbonApplication.class, args);
}
}
测试
-
启动eureka注册中心
-
通过改变端口启动多个provider-user实例（笔者使用的是8081，8082端口）
-
启动ribbon实例（笔者使用的是8083端口）
-
访问
-
访问http://localhost:8083/show/name=lanh
-
多次访问http://localhost:8083/log-user-instance，控制台输出如下：
