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一、在前一章的基础上启动eureka-server和两个eureka-client实例（在application.properties更改下端口号）新增一个模块service-ribbon

修改父工程的pom.xml文件在<Modules>节点处增加service-ribbon

           
    
     eureka-server
            
    
     eureka-client
            
    
     service-ribbon
        
   

service-ribbon的pom.xml的内容如下：

   
       
    
     4.0.0
        
    
     service-ribbon
        
    
     0.0.1-SNAPSHOT
        
    
     jar
        
    
     service-ribbon
        
    
     Demo project for Spring Boot
        
            
     
      com.example
             
     
      chapter2
             
     
      0.0.1-SNAPSHOT
         
        
            
     
      UTF-8
             
     
      UTF-8
             
     
      1.8
         
        
            
             
                 
      
       org.springframework.cloud
                  
      
       spring-cloud-starter-netflix-ribbon
              
             
             
                 
      
       org.springframework.cloud
                  
      
       spring-cloud-starter-netflix-eureka-client
              
         
        
            
                 
                      
       
        org.springframework.cloud
                       
       
        spring-cloud-dependencies
                       
       
        ${spring-cloud.version}
                       
       
        pom
                       
       
        import
                   
              
         
        
            
                 
                      
       
        org.springframework.boot
                       
       
        spring-boot-maven-plugin
                   
              
         
        
            
                 
      
       spring-milestones
                  
      
       Spring Milestones
                  
      
       https://repo.spring.io/milestone
                  
                      
       
        false
                   
              
         
    
   

配置文件application-properties内容如下：

#server 地址eureka.client.service-url.defaultZone=http://localhost:8001/eureka/#一个server 8001 两个client分别为8002 8003server.port=8004#实例名spring.application.name=service-ribbon

启动类ServiceRibbonApplication的内容如下：

package com.example;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;/** * 通过@EnableDiscoveryClient向服务中心注册；并且向程序的ioc注入一个bean * @author xiaobu */@EnableEurekaClient@EnableDiscoveryClient@SpringBootApplicationpublic class ServiceRibbonApplication {    public static void main(String[] args) {        SpringApplication.run(ServiceRibbonApplication.class, args);    }    /***     * @author xiaobu     * @date 2018/11/6 11:32     * @return org.springframework.web.client.RestTemplate     * @descprition restTemplate;并通过@LoadBalanced注解表明这个restRemplate开启负载均衡的功能。     * @version 1.0     */    @Bean    @LoadBalanced    RestTemplate restTemplate(){        return new RestTemplate();    }}

service-ribbon的目录结构如下

定义一个消费接口ClientService

package com.example.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.web.client.RestTemplate;/** * @author xiaobu * @version JDK1.8.0_171 * @date on  2018/11/6 11:34 * @descrption */@Servicepublic class ClientService {    @Autowired    RestTemplate restTemplate;    /***     * @author xiaobu     * @date 2018/11/6 11:42     * @param name 名字     * @return java.lang.String     * @descprition  直接用的程序名替代了具体的url地址，     * 在ribbon中它会根据服务名来选择具体的服务实例，     * 根据服务实例在请求的时候会用具体的url替换掉服务名     * @version 1.0     */    public String clientService(String name){        return restTemplate.getForObject("http://eureka-client/test?name=" + name, String.class);    }}

再定义个controller

package com.example.controller;import com.example.service.ClientService;import com.sun.org.glassfish.gmbal.ParameterNames;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;/** * @author xiaobu * @version JDK1.8.0_171 * @date on  2018/11/6 11:36 * @description V1.0 */@RestControllerpublic class ClientController {    @Autowired    ClientService clientService;    @GetMapping("/test")    public String test(@RequestParam String name){        return clientService.clientService(name);    }}

多次访问 出现的效果如下：

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