2019.01.18「小马哥技术周报」- 第十七期《Apache Dubbo 微服务系列之 Dubbo Spring Cloud 实现（下）》

Feign Dubbo 服务接口匹配分析

服务端应用名称：spring-cloud-alibaba-dubbo

Dubbo 服务

• 接口：org.springframework.cloud.alibaba.dubbo.service.EchoService

• 版本：1.0.0

• 协议：dubbo 以及 rest

@Service(version = "1.0.0", protocol = {"dubbo", "rest"})
@RestController
@Path("/")
public class DefaultEchoService implements EchoService {
    @Override
    @GetMapping(value = "/echo")
    @Path("/echo")
    @GET
    public String echo(@RequestParam @QueryParam("message") String message) {
        return RpcContext.getContext().getUrl() + " [echo] : " + message;
    }
}

客户端应用应用：spring-cloud-alibaba-dubbo

Feign 接口：

@FeignClient("spring-cloud-alibaba-dubbo")
public interface FeignEchoService {

    @GetMapping(value = "/echo")
    String echo(@RequestParam("message") String message);
}

指定的 Spring Cloud 应用名称：spring-cloud-alibaba-dubbo

REST URI：/echo

Params ： message

spring-cloud-alibaba-dubbo ->

配置信息 ID： spring-cloud-alibaba-dubbo-rest-metadata.json

内容：

[
  {
    "name": "providers:org.springframework.cloud.alibaba.dubbo.service.EchoService:1.0.0",
    "meta": [
      {
        "configKey": "EchoService#echo(String)",
        "method": "GET",
        "url": "/echo?message={message}",
        "headers": {},
        "indexToName": {
          "0": [
            "message"
          ]
        }
      },
      ...
    ]
  }
]

Feign.Builder

• 默认实现：feign.Feign.Builder
• Hystrix: feign.hystrix.HystrixFeign.Builder
• Sentinel:org.springframework.cloud.alibaba.sentinel.feign.SentinelFeign

feign.Feign.Builder -> Wrapper -> build()

FactoryBean<FeignEchoService> getType() == FeignEchoService