@FeignClient 的使用

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 添加依赖   

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

启用Feign

@EnableFeignClients

使用示例：注可以作为调用三方接口的统一入口

@FeignClient(value = "base")
//@FeignClient(name = "labelPrintClient", url = "${boton.printUrl}")
//@FeignClient(name = ClientUrl.ELN_SERVICE,configuration = FeignConfig.class)
public interface BaseFeignService {
    @GetMapping(value = "/user/name/{userId}")
    RestResponse<String> getUserName(@PathVariable Long userId);
}

增加拦截方式1：

@Aspect
@Component
public class FeignInterceptor {

    @Around("@within(feign))")
    public Object around(ProceedingJoinPoint point, FeignClient feign) throws Exception {
        Object obj = null;
        try {
            obj = point.proceed();
        } catch (Throwable e) {
            error( e.getMessage() , point, feign);
        }
        // 匹配并校验响应结果
        checkResult( obj, point,  feign);
        return obj;
    }

    public static void checkResult(Object obj,ProceedingJoinPoint point, FeignClient feign) throws Exception {
        if (null!=obj) {
            if(obj instanceof RestResponse){
                RestResponse response = (RestResponse)obj;
                if(response.getCode()!=0){
                    error( response.getResult() , point, feign);
                }
            }else {
                JSONObject jsonObj = JSONUtil.parseObj(obj);
                Integer code = jsonObj.getInt("code");
                if(code!=0){
                    error( jsonObj.get("result") , point, feign);
                }
            }
        }
    }

    /** api调用异常 / api正常响应:失败场景 */
    public static void error(Object cause , ProceedingJoinPoint point, FeignClient feign) throws Exception {
        throw new Exception(
                new StringBuffer()
                        .append(feign.value()).append(" 服务调用异常:").append(cause)
                        .append(";Api方法名：").append(point.getSignature().getName())
                        .append(";Api参数：" ).append(ArrayUtil.toString(point.getArgs()))
                        .toString()
        );
    }

} 

增加拦截方式2：只有请求的拦截

@Configuration
public class FeignConfig implements RequestInterceptor {
    @Override
    public void apply(RequestTemplate requestTemplate) {
        // 获取当前请求Spring信息
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        // 获取请求体
        HttpServletRequest request = Objects.requireNonNull(attributes).getRequest();
        // 获取Header、或参数等
        String token = request.getHeader("Authorization");
        //添加token
        requestTemplate.header("Authorization",token);
    }
}

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