史上最简单的SpringCloud教程 | 第二篇: 服务消费者（rest+ribbon）

你的名字 2022-06-14 00:37 218阅读 0赞

> 转载请标明出处：   
> [http://blog.csdn.net/forezp/article/details/69788938][http_blog.csdn.net_forezp_article_details_69788938]   
> 本文出自[方志朋的博客][Link 1]

在上一篇文章，讲了服务的注册和发现。在服务架构中，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也用到ribbon，当你使用@ FeignClient，ribbon自动被应用。

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、准备工作 ###

基于上一节的工程，启动eureka-server 工程；启动service-hi工程，它的端口为8762；将service-hi的配置文件的端口改为8763,并启动它，这时你会发现：service-hi在eureka-server注册了2个，这就相当于一个小的集群。访问localhost:8761如图所示：

![Paste\_Image.png][Paste_Image.png]

#### 三、建一个服务消费者 ####

重新新建一个spring-boot工程，取名为：service-ribbon;   
它的pom.xml文件如下：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.forezp</groupId>
        <artifactId>service-ribbon</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>service-ribbon</name>
        <description>Demo project for Spring Boot</description>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.5.2.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>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-eureka</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>Dalston.RC1</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-milestones</id>
                <name>Spring Milestones</name>
                <url>https://repo.spring.io/milestone</url>
                <snapshots>
                    <enabled>false</enabled>
                </snapshots>
            </repository>
        </repositories>
    
    
    </project>
    
    
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
       10
       11
       12
       13
       14
       15
       16
       17
       18
       19
       20
       21
       22
       23
       24
       25
       26
       27
       28
       29
       30
       31
       32
       33
       34
       35
       36
       37
       38
       39
       40
       41
       42
       43
       44
       45
       46
       47
       48
       49
       50
       51
       52
       53
       54
       55
       56
       57
       58
       59
       60
       61
       62
       63
       64
       65
       66
       67
       68
       69
       70
       71
       72
       73
       74
       75
       76
       77
       78
       79
       80
       81
       82
       83
      
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
       10
       11
       12
       13
       14
       15
       16
       17
       18
       19
       20
       21
       22
       23
       24
       25
       26
       27
       28
       29
       30
       31
       32
       33
       34
       35
       36
       37
       38
       39
       40
       41
       42
       43
       44
       45
       46
       47
       48
       49
       50
       51
       52
       53
       54
       55
       56
       57
       58
       59
       60
       61
       62
       63
       64
       65
       66
       67
       68
       69
       70
       71
       72
       73
       74
       75
       76
       77
       78
       79
       80
       81
       82
       83

向服务注册中心注册一个新的服务，这时service-ribbon既是服务提供者，也是服务消费者。配置文件application.yml如下：

eureka:
      client:
        serviceUrl:
          defaultZone: http://localhost:8761/eureka/
    server:
      port: 8764
    spring:
      application:
        name: service-ribbon
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
      
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9

在工程的启动类中,通过@EnableDiscoveryClient向服务中心注册；并且注册了一个bean: restTemplate;通过@ LoadBalanced注册表明，这个restRemplate是负载均衡的。

@SpringBootApplication
    @EnableDiscoveryClient
    public class ServiceRibbonApplication { 
    
        public static void main(String[] args) {
            SpringApplication.run(ServiceRibbonApplication.class, args);
        }
    
        @Bean
        @LoadBalanced
        RestTemplate restTemplate() {
            return new RestTemplate();
        }
    
    }
    
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
       10
       11
       12
       13
       14
       15
       16
      
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
       10
       11
       12
       13
       14
       15
       16

这时我们需要测试下,建一个service类：

@Service
    public class HelloService { 
    
        @Autowired
        RestTemplate restTemplate;
    
        public String hiService(String name) {
            return restTemplate.getForObject("http://SERVICE-HI/hi?name="+name,String.class);
        }
    
    }
    
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
       10
       11
       12
      
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
       10
       11
       12

通过restTemplate.getForObject方法，service-ribbon 就可以调用service-hi的方法了。并且在调用的工程中并之需要写服务的名，而不是具体的ip.

写一个controller:

/** * Created by fangzhipeng on 2017/4/6. */
    @RestController
    public class HelloControler { 
    
        @Autowired
        HelloService helloService;
        @RequestMapping(value = "/hi")
        public String hi(@RequestParam String name){
            return helloService.hiService(name);
        }
    
    
    }
    
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
       10
       11
       12
       13
       14
       15
       16
       17
      
     
      
       1
       2
       3
       4
       5
       6
       7
       8
       9
       10
       11
       12
       13
       14
       15
       16
       17

访问[http://localhost:8764/hi?name=forezp][http_localhost_8764_hi_name_forezp],浏览器交替显示：

> hi forezp,i am from port:8762
> 
> hi forezp,i am from port:8763

这说明当我们通过调用restTemplate.getForObject(“[http://SERVICE-HI/hi?name=][http_SERVICE-HI_hi_name]“+name,String.class)，获取service-hi的方法时，已经做了负载均衡，访问了不同的端口的服务。

### 四、此时的架构 ###

![此时架构图.png][.png]

*  一个服务注册中心，eureka server,端口为8761
 *  service-hi工程跑了两个副本，端口分别为8762,8763，分别向服务注册中心注册
 *  sercvice-ribbon端口为8764,向服务注册中心注册
 *  当sercvice-ribbon通过restTemplate调用service-hi的hi接口时，因为用ribbon进行了负载均衡，会轮流的调用service-hi：8762和8763 两个端口的hi接口；

源码下载：[https://github.com/forezp/SpringCloudLearning/tree/master/chapter2][https_github.com_forezp_SpringCloudLearning_tree_master_chapter2]

### 五、参考资料 ###

本文参考了以下：

[spring-cloud-ribbon][]

[springcloud ribbon with eureka][]

[服务消费者][Link 2]

### 优秀文章推荐： ###

*  [史上最简单的 SpringCloud 教程 | 终章][SpringCloud _ _]
 *  [史上最简单的 SpringCloud 教程 | 第一篇: 服务的注册与发现（Eureka）][SpringCloud _ _ _ _Eureka]
 *  [史上最简单的SpringCloud教程 | 第七篇: 高可用的分布式配置中心(Spring Cloud Config)][SpringCloud_ _ _ _Spring Cloud Config]

[http_blog.csdn.net_forezp_article_details_69788938]: http://blog.csdn.net/forezp/article/details/69788938
[Link 1]: http://blog.csdn.net/forezp
[Paste_Image.png]: /images/20220614/a1831b06a96e4125a19274a7788d5237.png
[http_localhost_8764_hi_name_forezp]: http://localhost:8764/hi?name=forezp
[http_SERVICE-HI_hi_name]: http://service-hi/hi?name=
[.png]: /images/20220614/1108d244c723492090a4d66135f1d6c1.png
[https_github.com_forezp_SpringCloudLearning_tree_master_chapter2]: https://github.com/forezp/SpringCloudLearning/tree/master/chapter2
[spring-cloud-ribbon]: http://projects.spring.io/spring-cloud/spring-cloud.html#spring-cloud-ribbon
[springcloud ribbon with eureka]: http://blog.csdn.net/liaokailin/article/details/51469834
[Link 2]: http://blog.didispace.com/springcloud2/
[SpringCloud _ _]: http://blog.csdn.net/forezp/article/details/70148833
[SpringCloud _ _ _ _Eureka]: http://blog.csdn.net/forezp/article/details/69696915
[SpringCloud_ _ _ _Spring Cloud Config]: http://blog.csdn.net/forezp/article/details/70037513