1.定制设计负载均衡源码

2.新⼀定制设计代负载均衡组件Open-Feign

• 原先ribbon定制设计代码存在的问题：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Ribbon
• Nacos⽀持Feign,可以直接集成实现负载均衡的效果

3.集成实现远程⽅法调⽤

• 加⼊依赖

        <!--引入feign-->        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-openfeign</artifactId>        </dependency>
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• 配置注解

启动类增加 @EnableFeignClients
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• 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);}
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• 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<ServiceInstance> 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;    }}
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• 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