spring-cloud微服务项目实战（5）-feign简化客户端调用

目标：

改进上一章讲的客户端调用方式，集成feign，简化客户端调用

简介：

Fegin是一个声明式的web服务客户端，它使得编写web服务客户端变得更加容易，其形态类似于mybatis对于dao层的封装。

开工：

1. 在commons创建返回vo模型，以便多系统共用,具体业务意义不在这里讨论

--------------------------------------请求vo----------------------------------

package open.template.work.commons.vo.udm.request;

import open.template.work.commons.vo.udm.BaseRequestVo;

public class TaskRequestVo extends BaseRequestVo {

    /**
     * 本服务应用名
     */
    private String appName;

    /**
     * 任务桶id
     */
    private String bucketId;

      。。。。
}



--------------------------------------返回vo----------------------------------

package open.template.work.commons.vo.udm.resposne;

import open.template.work.commons.vo.udm.BaseResponseVo;

/**
 * 任务信息
 */
public class TaskReponseVo extends BaseResponseVo {

    /**
     * 任务桶id
     */

    private String bucketId;

    /**
     * 任务id
     */
    private String taskId;

    /**
     * 状态
     */
    private String status;
    
      。。。。。。

}

2. 服务端添加新的restapi，先模拟返回此vo，因为入参是对象，所以需要添加@RequestBody 注解

@RestController
public class TaskInfoApi {

    @PostMapping("/task/get")
    public TaskReponseVo popTaskInfo(@RequestBody  TaskRequestVo vo){
        System.out.println("尝试获取桶"+vo.getBucketId()+"任务数据");
        TaskReponseVo taskInfoDto = new TaskReponseVo();
        taskInfoDto.setStatus("1");
        taskInfoDto.setTaskId(UUID.randomUUID().toString());
        return taskInfoDto;
    }
}

3. 客户端添加feign配置，

首先添加feign依赖

        
            org.springframework.cloud
            spring-cloud-starter-feign
        

然后添加启动feign注解，并指定扫描的feign包

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients(basePackages = "open.template.work.udm.client.feign")
public class UdmClientApplication {

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


    @Bean
    public IRule ribbonRoundRobinRule() {
        return new RandomRule();
    }


}

添加feign声明式接口

package open.template.work.udm.client.feign;

import open.template.work.commons.constants.CloudServerDirectory;
import open.template.work.commons.vo.udm.request.TaskRequestVo;
import open.template.work.commons.vo.udm.resposne.TaskReponseVo;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;

@FeignClient(name = CloudServerDirectory.UDM_SERVER)
public interface UdmServerTaskFegin {

    @PostMapping("/task/get")
    TaskReponseVo getTaskInfo(@RequestBody TaskRequestVo vo);
}

最后在service层和api层添加对应调用测试逻辑，可以看到此时LoadBalancerClient方式和feign方式是共存的，feign会自动集成eureka和ribbon，所以此时的负载策略就是上章通过IRule和配置文件指定的负载规则，对于eureia我们通过@FeignClient(name = CloudServerDirectory.UDM_SERVER)注解在feign已指定，不需在拼接url，完美集成。

package open.template.work.udm.client.service.impl;

import open.template.work.commons.constants.CloudServerDirectory;
import open.template.work.commons.http.RestTemplateFactory;
import open.template.work.commons.vo.udm.request.TaskRequestVo;
import open.template.work.commons.vo.udm.resposne.TaskReponseVo;
import open.template.work.udm.client.feign.UdmServerClient;
import open.template.work.udm.client.feign.UdmServerTaskFegin;
import open.template.work.udm.client.service.UdmServerService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.stereotype.Service;

@Service
public class UdmServerServiceImpl implements UdmServerService {

    @Autowired
    private LoadBalancerClient loadBalancerClient;


    @Autowired
    private UdmServerClient udmServerClient;

    @Autowired
    private UdmServerTaskFegin udmServerTaskClient;


    @Override
    public String checkServerInfo() {
        ServiceInstance instance = loadBalancerClient.choose(CloudServerDirectory.UDM_SERVER);
        return RestTemplateFactory.getTemplate().getForObject(CloudServerDirectory.getServerUrl(instance.getHost(),instance.getPort())+"hello",String.class);
    }

    @Override
    public String checkServer2(){
        return udmServerClient.hello();
    }

    @Override
    public TaskReponseVo getTaskInfo(String bucketId) {
        TaskRequestVo vo=new TaskRequestVo();
        vo.setBucketId(bucketId);
        return udmServerTaskClient.getTaskInfo(vo);
    }
}

3. 都配了，启动服务测试一下

客户端获取到的数据

服务端日志：

服务端日志

完工！