spring cloud 入门实践系列 - ribbon

àì夳堔傛蜴生んèń 2022-06-12 09:29 204阅读 0赞

> Ribbon is a client side IPC library that is battle-tested in cloud. It provides the following features  
> Load balancing  
> Fault tolerance  
> Multiple protocol (HTTP, TCP, UDP) support in an asynchronous and reactive model  
> Caching and batching

## 创建ribbon测试项目 ##

### 项目结构如图 ###

![这里写图片描述][SouthEast]

### 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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.zhang</groupId>
        <artifactId>ribbontest</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>ribbontest</name>
        <description>Demo project for Spring Boot</description>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.5.4.RELEASE</version>
            <relativePath/> 
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
            <spring-cloud.version>Dalston.SR1</spring-cloud.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-ribbon</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-eureka</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>

### 属性配置文件application.properties ###

**server.port=7071代表RibbontestApplication暴露在7071端口**

spring.application.name=ribbon
    server.port=7071
    eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/servicehello.ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RandomRule

### 暴露服务调用接口 ###

package com.zhang.web;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.client.RestTemplate;
    
    /** * Created by zhangxiaolong on 17/7/20. */
    @RestController
    public class ConsumerClass { 
        @Autowired
        private RestTemplate restTemplate;
    
        @Autowired
        private LoadBalancerClient loadBalancerClient;
    
        @RequestMapping(value = "/hello", method = RequestMethod.GET)
        public String hello(@RequestParam String name) {
            this.loadBalancerClient.choose("service-hello");//随机访问策略
            return restTemplate.getForEntity("http://service-hello/hello?name="+name, String.class).getBody();
    
        }
    }

### 应用程序运行入口 ###

package com.zhang;
    
    import com.netflix.loadbalancer.IRule;
    import com.netflix.loadbalancer.RandomRule;
    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;
    
    @EnableEurekaClient
    @SpringBootApplication
    public class RibbontestApplication { 
    
        @Bean
        @LoadBalanced
        RestTemplate restTemplate() {
            return new RestTemplate();
        }
    
        @Bean
        public IRule ribbonRule() {
            return new RandomRule();
        }
    
        public static void main(String[] args) {
            SpringApplication.run(RibbontestApplication.class, args);
        }
    }

## 创建service-hello服务 ##

#### 使用eureka作为注册中心，暴露在端口8761 ####

#### 启动两个service-hello服务，分别暴露在8762和8763端口 ####

![这里写图片描述][SouthEast 1]  
可以看到service-hello服务，Availability Zones数量是2，也就是有两个实例在提供服务。

##### 8762提供服务代码 #####

@RequestMapping("hello")
        public String hello(@RequestParam String name){
            return "hello "+name+",from service provider 1";
        }

##### 8763提供服务代码 #####

@RequestMapping("hello")
        public String hello(@RequestParam String name){
            return "hello "+name+",from service provider 2";
        }

## 测试和验证 ##

1 启动RibbontestApplication中的main函数  
![这里写图片描述][SouthEast 2]  
2 浏览器中输入  
[http://172.16.153.1:7071/hello?name=%E5%BC%A0%E5%B0%8F%E9%BE%99][http_172.16.153.1_7071_hello_name_E5_BC_A0_E5_B0_8F_E9_BE_99]

![这里写图片描述][SouthEast 3]

![这里写图片描述][SouthEast 4]

## 结论 ##

1 ribbon可以作为eureka服务的客户端，可以调通注册在eureka服务器上的服务  
2 ribbon天生带着负载均衡的支持，负载策略可配置。  
RibbontestApplication中ribbonRule方法返回的RandomRule即是随机策略。  
其他负载策略

<table> 
 <thead> 
  <tr> 
   <th>负载策略</th> 
   <th align="center">备注</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>RoundRobinRule</td> 
   <td align="center">轮询策略</td> 
  </tr> 
  <tr> 
   <td>AvailabilityFilteringRule</td> 
   <td align="center">可用性过滤策略，可用性越强优先</td> 
  </tr> 
  <tr> 
   <td>WeightedResponseTimeRule</td> 
   <td align="center">响应时间权重策略，响应时间越长，权重越小</td> 
  </tr> 
 </tbody> 
</table>

[SouthEast]: /images/20220612/9f207e9cc9554d9aa073f7b56ac07517.png
[SouthEast 1]: /images/20220612/6dcf9f61a26148e391a4773e2e70b0a9.png
[SouthEast 2]: /images/20220612/4dffb06515e1463480326395a2a7454c.png
[http_172.16.153.1_7071_hello_name_E5_BC_A0_E5_B0_8F_E9_BE_99]: http://172.16.153.1:7071/hello?name=%E5%BC%A0%E5%B0%8F%E9%BE%99
[SouthEast 3]: /images/20220612/779f92aa15324fc699bb505383d67d1c.png
[SouthEast 4]: /images/20220612/c7f1cad52b094fda8451b4ad2e0f3344.png