// 微服務(wù)A controller 已經(jīng)使用@restController修飾
@PostMapping(value="/getAllQuestionBank",produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
	public List<QuestionBankDto> getAllQuestionBank(){
		return baseinfoQuestionMange.getAllQuestionBank();
}
 
// 微服務(wù)B feign接口 使用String進(jìn)行接受
@PostMapping(value="/baseinfo/getAllQuestionBank")
String getAllQuestionBank();
 
// 微服務(wù)B 當(dāng)需要調(diào)用feign信息時(shí)需要強(qiáng)轉(zhuǎn)成List<QuestionBankDto>格式 
 
// 調(diào)用微服務(wù)獲取題庫章節(jié)信息，該處強(qiáng)制使用try catch進(jìn)行包裹
String questionBankInfo = baseInfoApi.getAllQuestionBank();
List<QuestionBankDto> mysqlQuestionBank = objectMapper.readValue(questionBankInfo,new TypeReference<ArrayList<QuestionBankDto>>(){});

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

@FeignClient(name = "weixinTokenClient", url = "https://qyapi.weixin.qq.com/cgi-bin")
public interface IWeiXinTokenClient {
   /**
    * 獲取應(yīng)用的token
    * @param corpid
    * @param corpsecret
    * @return
    */
   @RequestMapping(value = "/gettoken", method = RequestMethod.GET)
   WeiXinTokenResultModel getToken(@RequestParam String corpid, @RequestParam String corpsecret);
}

@FeignClient(value = "paasUserFacade", contextId = "lemur-paas", path = "/im/user")
public interface IPaasUserFacade extends IBaseController<PaasUserRequestModel> {
}

<T> T getTarget() {
  FeignContext context = this.applicationContext.getBean(FeignContext.class);
  Feign.Builder builder = feign(context);
  if (!StringUtils.hasText(this.url)) {
   if (StringUtils.hasText(this.contextId) && !this.name.startsWith("http")){
    this.url =  "http://" + this.contextId;
   }else if (StringUtils.hasText(this.contextId)){
    this.url =  this.contextId;
   } else if (!this.name.startsWith("http")) {
    this.url = "http://" + this.name;
   }
   else {
    this.url = this.name;
   }
   this.url += cleanPath();
   return (T) loadBalance(builder, context,
     new HardCodedTarget<>(this.type, this.name, this.url));
  }
  if (StringUtils.hasText(this.url) && !this.url.startsWith("http")) {
   this.url = "http://" + this.url;
  }
  String url = this.url + cleanPath();
  Client client = getOptional(context, Client.class);
  if (client != null) {
   if (client instanceof LoadBalancerFeignClient) {
    // not load balancing because we have a url,
    // but ribbon is on the classpath, so unwrap
    client = ((LoadBalancerFeignClient) client).getDelegate();
   }
   builder.client(client);
  }
  Targeter targeter = get(context, Targeter.class);
  return (T) targeter.target(this, builder, context,
    new HardCodedTarget<>(this.type, this.name, url));
 }

ReflectiveFeign.invoke->
SynchronousMethodHandler.invoke->
executeAndDecode->decode(解析對(duì)象)->
ResponseEntityDecoder.decode->
SpringDecoder.decode->
HttpMessageConverterExtractor.extractData(返回泛型)->
FastJsonHttpMessageConverter(真正的解析器).read(type,clazz,inputMessage)->
parseObject(is)

 <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <exclusions>
                <exclusion>
                    <artifactId>spring-boot-starter-web</artifactId>
                    <groupId>org.springframework.boot</groupId>
                </exclusion>
            </exclusions>
        </dependency>