spring-cloud学习之3.使用feign实现负载均衡

一：准备

1.feign依赖

<!--feign-->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

2.web

 　　　　 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

3.eureka-cli

<!--eureka 客户端 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

4.配置

server:
  port: 3001
spring:
  application:
    name: dandelion-api

eureka:
  client:
    service-url:
      defaultZone: http://localhost:1001/eureka
  instance:
    instance-id:  ${spring.application.name}:${server.port}
    prefer-ip-address: true  

feign:
  #开启feign熔断支持
  hystrix:
    enabled: true

5.启动类

/**
 * api
 *
 * @author jiang
 */
@SpringBootApplication
@EnableFeignClients
public class DandelionApiApplication {

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

}

6.案例

/**
 * 部门信息
 *
 * @author jiang
 */
@RestController
@RequestMapping("/dept")
public class SysDeptController {

    @Autowired
    private ISysDeptService deptService;


    @RequestMapping("/list")
    public R list(SysDept dept) {

        System.out.println(dept.getPageNum() + ":" + dept.getPageSize());
        return deptService.selectDeptList(dept);
    }

}

/**
 * <p>
 * 部门表 服务类
 * </p> 
　　
 *
 * @author jiang
 * @since 2020-03-18
 */
@FeignClient(value = ServiceNameConst.DANDELION_SERVICE, fallback = ISysDeptServiceFallBackImpl.class)
public interface ISysDeptService {

    /**
     * 查询部门管理数据
     *
     * @param dept 部门信息
     * @return 部门信息集合
     */
    @RequestMapping("/dept/list")
    R selectDeptList(SysDept dept);


}

public static final String DANDELION_SERVICE = "dandelion-service";  服务名

实现类即是断路回应

/**
 * 断路
 *
 * @author jiang
 */
@Component
public class ISysDeptServiceFallBackImpl implements ISysDeptService {
    @Override
    public R selectDeptList(SysDept dept) {

        return R.error();
    }
}