SpringCloud系列教程04-服务调用之Ribbon

电玩女神 2024-04-17 21:07 68阅读 0赞

### 文章目录 ###

*   *  概述
     *  service-producer
     *  service-consumer
     *  ribbon/feign/http比较
     *  测试
     *  项目源码
     *  参考

--------------------

## 概述 ##

在第二篇文章**SpringCloud服务调用之Feign**中，我们介绍了SpringCloud中使用feign进行服务调用的案例。当时还介绍了feign是基于ribbon的。

这一篇，我们就来看看通过`原生`的ribbon是怎么进行服务调用的。

官方文档：[https://projects.spring.io/spring-cloud/spring-cloud.html\#spring-cloud-ribbon][https_projects.spring.io_spring-cloud_spring-cloud.html_spring-cloud-ribbon]

> 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.

ribbon可以实现服务调用和负载均衡，而feign集成了ribbon。

也就是说：feign是基于ribbon的，ribbon的调用可以理解是SpringCloud原生的服务调用。

注：这一篇，我们基于上一篇[SpringCloud服务注册之Consul][SpringCloud_Consul]中的consul来实现这么一个demo。

**需要**：consul、service-producer服务（引入consul）、service-consumer服务（引入consul和ribbon）

**版本**：SpringBoot 2.0.7.RELEASE与SpringCloud Finchely.RELEASE

--------------------

## service-producer ##

服务生产者与上一节相同，需要引入`consul-discovery`:

<properties>
            <java.version>1.8</java.version>
            <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-consul-discovery</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </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>

配置文件：

server:
      port: 8200
    spring:
      application:
        name: service-producer
      cloud:
        consul:
          host: localhost
          port: 8500
          discovery:
            register: true
            instance-id: ${ spring.application.name}:${ server.port}
            service-name: ${ spring.application.name}
            port: ${ server.port}

启动类添加`@EnableDiscoveryClient`注解：

package com.example.serviceproducer;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    
    @SpringBootApplication
    @EnableDiscoveryClient
    public class ServiceProducerApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(ServiceProducerApplication.class, args);
        }
    
    }

测试接口：

package com.example.serviceproducer;
    
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping(value = "producer")
    public class HelloAction { 
    
        @GetMapping(value = "hello/{name}")
        public String hello(@PathVariable String name) { 
            return "Hello " + name + ", this is response from hello by service-producer.";
        }
    }

启动服务后，测试一下：  
![在这里插入图片描述][20190901104340690.png]

--------------------

## service-consumer ##

服务消费者需要引入`consul-discovery`和`netflix-ribbon`:

<properties>
            <java.version>1.8</java.version>
            <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-consul-discovery</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
            </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>

配置文件与**service-producer**基本相同：

server:
      port: 8201
    spring:
      application:
        name: service-consumer
      cloud:
        consul:
          host: localhost
          port: 8500
          discovery:
            register: true
            service-name: ${ spring.application.name}
            instance-id: ${ spring.application.name}:${ server.port}
            port: ${ server.port}

同样在启动类上添加`@EnableDiscoveryClient`注解。

下面就有所不同了，还需要注入一个`RestTemplate`的Bean实例——这个类来自`spring-boot-starter-web`包：

package com.example.serviceconsumer;
    
    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.cloud.netflix.hystrix.EnableHystrix;
    import org.springframework.context.annotation.Bean;
    import org.springframework.web.client.RestTemplate;
    
    @SpringBootApplication
    @EnableDiscoveryClient
    public class ServiceConsumerApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(ServiceConsumerApplication.class, args);
        }
    
        /** * 注入RestTemplate Bean并开启负载均衡 * @return */
        @Bean
        @LoadBalanced
        public RestTemplate restTemplate() { 
            return new RestTemplate();
        }
    
    }

注：也可以不采用注入而在使用的时候直接`new RestTemplate()`。

看一下我编写的测试接口：

package com.example.serviceconsumer;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.client.RestTemplate;
    
    @RestController
    @RequestMapping(value = "consumer")
    public class ConsumerAction { 
    
        @Autowired
        private RestTemplate restTemplate;
    
        @GetMapping(value = "test")
        public String test(String name) { 
            // 利用RestTemplate，直接请求对应的service-name/request
            String producerRes = restTemplate.getForObject("http://service-producer/producer/hello/" + name, String.class);
            String res = "service-consumer服务调用service-producer服务，hello接口返回数据：" + producerRes;
            System.out.println(res);
            return res;
        }
    }

上面的示例中，使用了`restTemplate.getForObject("http://service-producer/producer/hello/" + name, String.class);`来调用服务`service-producer`的路径为`producer/hello/{name}`的接口。

--------------------

## ribbon/feign/http比较 ##

与普通的HTTP请求比较：HTTP请求使用`http://ip:port/path`的方式请求，而ribbon则使用`http://service-name/path`的方式。

与feign请求比较：

@FeignClient(name = "service-provider")
    public interface HelloRemote { 
    
        @GetMapping(value = "hello/{name}")
        public String hello(@PathVariable("name") String name);
    }

注：feign的使用参考——[SpringCloud系列教程02-服务调用之feign][SpringCloud_02-_feign]

feign是使用`@FeignClient`来声明式地声明一个与被调用服务接口相同的接口，然后直接调用这个接口。而ribbon是直接通过路径调用。

--------------------

## 测试 ##

启动service-consumer后，看一下consul：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI4Mzc5ODA5_size_16_color_FFFFFF_t_70]

测试consumer服务调用producer服务：  
![在这里插入图片描述][20190901104429890.png]

至此，基于ribbon进行服务调用的示例已经完成。具体可以参考下面地址的源码。

--------------------

## 项目源码 ##

[https://github.com/laolunsi/spring-cloud-examples/tree/master/04-ServiceConsumeRibbon][https_github.com_laolunsi_spring-cloud-examples_tree_master_04-ServiceConsumeRibbon]

--------------------

## 参考 ##

> 1.  方志朋-服务消费者（rest+ribbon）(Finchley版)：[https://blog.csdn.net/forezp/article/details/81040946][https_blog.csdn.net_forezp_article_details_81040946]

[https_projects.spring.io_spring-cloud_spring-cloud.html_spring-cloud-ribbon]: https://projects.spring.io/spring-cloud/spring-cloud.html#spring-cloud-ribbon
[SpringCloud_Consul]: https://blog.csdn.net/qq_28379809/article/details/100174754
[20190901104340690.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/b2945b6524bb4b30b49c4cd144e53db9.png
[SpringCloud_02-_feign]: https://blog.csdn.net/qq_28379809/article/details/100173704
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI4Mzc5ODA5_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/2a79584e2fa0406aa5183441e9643ae3.png
[20190901104429890.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/329058130c3745bbb1f5ab7d10494234.png
[https_github.com_laolunsi_spring-cloud-examples_tree_master_04-ServiceConsumeRibbon]: https://github.com/laolunsi/spring-cloud-examples/tree/master/04-ServiceConsumeRibbon
[https_blog.csdn.net_forezp_article_details_81040946]: https://blog.csdn.net/forezp/article/details/81040946