第五章 负载均衡进阶之 Ribbon和Feign实战

原先ribbon代码存在的问题：不规范，⻛格不统⼀，维护
性⽐较差什么是Feign
SpringCloud提供的伪http客户端(本质还是⽤http)，封装了Http调⽤流程，更适合⾯向接⼝化让⽤Java接⼝注解的⽅式调⽤Http请求.不⽤像Ribbon中通过封装HTTP请求报⽂的⽅式调⽤ Feign默认集成了RibbonNacos⽀持Feign,可以直接集成实现负载均衡的效果 3.集成Feign实现远程⽅法调⽤

加⼊依赖

        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        

配置注解

启动类增加 @EnableFeignClients

增加⼀个接⼝

//服务名称记得和nacos保持⼀样
@FeignClient(name="xdclass-video-service")
public interface VideoService {
    @GetMapping(value = "/api/v1/video/find_by_id")
    Video findById(@RequestParam("videoId") int videoId);
    //订单服务这边
    @PostMapping(value = "/api/v1/video/save")
    int saveVideo(@RequestBody Video video);
}

修改Controller

@RestController
@RequestMapping("api/v1/video_order")
public class OrderController {
    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private DiscoveryClient discoveryClient;
    @Autowired
    private VideoService videoService;
    @RequestMapping("find_by_id")
    public Object findById(int videoId){
        //Video video = restTemplate.getForObject("http://localhost:9000/api/v1/video/find_by_id?videoId="+videoId, Video.class);
        //List list =  discoveryClient.getInstances("xdclass-video-service");
        //ServiceInstance serviceInstance = list.get(0);
        //Video video = restTemplate.getForObject("http://xdclass-video-service/api/v1/video/find_by_id?videoId="+videoId, Video.class);
        Video video = videoService.findById(videoId);
        VideoOrder videoOrder = new VideoOrder();
        videoOrder.setVideoId(video.getId());
        videoOrder.setVideoTitle(video.getTitle());
        videoOrder.setCreateTime(new Date());
        videoOrder.setServerInfo(video.getServerInfo());
        return videoOrder;
    }
    
    @PostMapping("save")
    public Object save(@RequestBody Video video){
       int rows = videoService.saveVideo(video);
        Map map = new HashMap<>();
        map.put("rows",rows);
        return map;
    }
}

Ribbon和feign两个的区别和选择
选择feign
默认集成了ribbon
写起来更加思路清晰和⽅便
采⽤注解⽅式进⾏配置，配置熔断等⽅式⽅便