Day17_13_SpringCloud教程之Ribbon实战

拼搏现实的明天。 2024-02-19 20:45 36阅读 0赞

## Ribbon实战 ##

### 注意: ###

本SpringCloud系列博客案例代码,是建立在一个共同的项目中,以后所有模块公共依赖包不再赘述,具体请参考Eureka实战篇.

[https://blog.csdn.net/syc000666/article/details/95388985][https_blog.csdn.net_syc000666_article_details_95388985]

<parent>
       <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-parent</artifactId>
          
          <version>2.0.3.RELEASE</version>
          <relativePath/>
    </parent>
    
    <properties>
       
       <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
       <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
       <encoding>UTF-8</encoding>
       <java.version>1.8</java.version>
       <maven.compiler.source>1.8</maven.compiler.source>
       <maven.compiler.target>1.8</maven.compiler.target>
       <lombok.version>1.16.20</lombok.version>
    
       
       <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
    </properties>
    
    <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>
    
    <dependencies>
       
          
          
          
    
          
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
          </dependency>
    
          
          <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
             <version>${lombok.version}</version>
          </dependency>
    
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
    </dependencies>
    
    <build>
       <plugins>
          <plugin>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-maven-plugin</artifactId>
          </plugin>
       </plugins>
    </build>

### 一. 创建Eureka Server模块 ###

#### 1. pom.xml中添加依赖 ####

<dependencies>
       
       <dependency>
          <groupId>org.springframework.cloud</groupId>
          <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
       </dependency>
    </dependencies>

#### 2. 创建配置文件 ####

server:
      port: 8761
    spring:
      application:
        name: eurka-server
    eureka:
      instance:
        hostname: localhost
      client:
        registerWithEureka: false
        fetchRegistry: false
        serviceUrl:
          defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

#### 3. 创建入口类 ####

package com.syc.cloud;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
    
    /**
     * 跟一一哥学SpringCloud微服务
     */
    @EnableEurekaServer
    @SpringBootApplication
    public class EurekaApplication {
    
        public static void main(String[] args){
            SpringApplication.run(EurekaApplication.class,args);
        }
    }

#### 4. 项目结构 ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70][]

### 二. 创建一个服务提供者 ###

#### 1. 添加依赖 ####

#### 2. 创建配置文件 ####

server:
      port: 8762
    spring:
      application:
        name: eureka-provider
    eureka:
      instance:
        hostname: localhost
      client:
        serviceUrl:
          defaultZone: http://localhost:8761/eureka/

注意:

**本案例中共有2个服务提供者,代码一样,端口号分别为8762,8763,我们是在一个机器上部署两个不同端口号的服务实例.**

#### 3. 创建对外提供服务的接口 ####

package com.syc.cloud.web;
    
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class HelloController {
    
        @Value("${server.port}")
        private String port;
    
        @RequestMapping("/hello")
        public String sayHi(@RequestParam String name) {
            return "Hello," + name + "! This is " + port;
        }
    
    }

#### 4. 创建入口类 ####

#### 5. 项目结构 ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 1][]

### 三. 创建一个服务消费者 ###

#### 1. 添加依赖 ####

<dependencies>
       <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-netflix-ribbon</artifactId>
        </dependency>
    </dependencies>

#### 2. 创建配置文件 ####

server:
      port: 8764
    spring:
      application:
        name: eureka-ribbon
    eureka:
      instance:
        hostname: localhost
      client:
        serviceUrl:
          defaultZone: http://localhost:8761/eureka/

#### 3. 创建远程调用的service ####

package com.syc.cloud.service;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.web.client.RestTemplate;
    
    /**
     * 远程调用eureka-provider的方法
     */
    @Service
    public class RibbonService {
    
        @Autowired
        private RestTemplate restTemplate;
    
        public String helloService(String name) {
            return restTemplate.getForObject("http://eureka-provider/hello?name="+name,String.class);
        }
    }

#### 4. 创建web层的controller ####

package com.syc.cloud.web;
    
    import com.syc.cloud.service.RibbonService;
    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 HelloController {
    
        @Autowired
        private RibbonService helloService;
    
        @RequestMapping(value = "/hello")
        public String hello(@RequestParam String name){
    
            return helloService.helloService(name);
        }
    
    }

#### 5. 创建入口类 ####

package com.syc.cloud;
    
    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.eureka.EnableEurekaClient;
    import org.springframework.context.annotation.Bean;
    import org.springframework.web.client.RestTemplate;
    
    /**
     *
     */
    @SpringBootApplication
    @EnableDiscoveryClient //注意:必须是@EnableDiscoveryClient注解,不能是@EnableEurekaClient,否则无法实现负载均衡.
    //@EnableEurekaClient
    public class ServiceRibbonApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(ServiceRibbonApplication.class, args);
        }
    
        //创建负载均衡组件
        @Bean
        @LoadBalanced
        public RestTemplate restTemplate() {
            return new RestTemplate();
        }
    
    }

注意:

**入口类必须添加@EnableDiscoveryClient注解,不能是@EnableEurekaClient注解,否则无法实现负载均衡.**

### 四. 一个服务实例多端口同时启动配置 ###

为了创建高可用的微服务,我们配置同一个服务实例按多个端口同时启动.

#### 1. 首先配置8762端口的服务实例. ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 2][]

#### 2. 然后复制8762端口的配置. ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 3][]

修改端口号为8763.

#### 3. 创建一个Compound ####

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 4][]

注意就可以通过Compound来同时启动2个服务实例了.

### 五. 启动4个服务 ###

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 5][]

![Image 1][]此时已经成功的启动了4个服务实例.

#### 接口测试: ####

第一次访问接口,端口号8762.  
![Image 1][]![20190714221103381.png][]

第2次访问接口,端口号8763.  
![Image 1][]![20190714221112966.png][]

可见默认采用的是轮询的负载均衡方式.

### 六. 项目架构 ###

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 6][]

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

[https_blog.csdn.net_syc000666_article_details_95388985]: https://blog.csdn.net/syc000666/article/details/95388985
[Image 1]: 
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/2c32b2af37864b9ca4c7198181da338a.png
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[20190714221103381.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/ad7c3ffbc3644a1fa80aec7a1dac6bea.png
[20190714221112966.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/24247f156c2b4546866de0f50a4ff0d5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 6]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/ec43f9eb42904f718a77a09b8b2ef953.png