五、SpringCloud服务调用(Feign接口对象模式)

第一步、在当前项目pom.xml中添加spring-cloud-starter-feign的jar包

<dependencies>
    <!-- ribbon -->
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-eureka</artifactId>
      <version>1.3.4.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-ribbon</artifactId>
      <version>1.3.4.RELEASE</version>
    </dependency>

    <!-- feign调用 -->
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-feign</artifactId>
      <version>1.3.4.RELEASE</version>
    </dependency>

</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
          <groupId>org.springframework.cloud</groupId>
          <artifactId>spring-cloud-starter-parent</artifactId>
          <version>Brixton.SR5</version>
          <type>pom</type>
        </dependency>
    </dependencies>

第二步：在application.properties中配置eureka参数

eureka.client.serviceUrl.defaultZone=http://localhost:7777/eureka

第三步：创建cn.xxx.xxx.remote包，在创建定义xxxRemote远程Feign接口，追加@FeignClient标记

@FeignClient(name="SUBJECT-SERVICE")//指定注册服务名
public interface SubjectRemote {

    //方法参考Controller定义编写
    @RequestMapping(value="/subject",method=RequestMethod.GET)
    public ResponseResult loadSubjects();

}

第四步：直接在Controller中注入SubjectRemote (远程Feign对象调用远程服务)接口

@Controller
@RequestMapping("/exam")
public class ExamController {
  
  @Autowired
  private SubjectRemote subjectRemote;
  
  
  @RequestMapping("/home.html")
  public String home(String token,ModelMap model){


    //调用http://localhost:8885/subject请求获取所有学科信息
    //url规则： http://注册服务名/请求名
    ResponseResult result = subjectRemote.loadSubjects();

    ……

    //将数据存入Model
    model.put("result", result);
    return "home";//templates/home.html
  }
  
}

第五步、添加@EnableFeignClients和@EnableDiscoveryClient标记到启动类

@EnableFeignClients//启用Feign接口模式调用服务
@EnableDiscoveryClient//启用服务注册和查找
@SpringBootApplication
public class ExamWebBootApplication {

    public static void main(String[] args){
        SpringApplication.run(ExamWebBootApplication.class, args);
    }

}

第六步、启动各服务测试