Feign如何实现第三方的HTTP请求

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

# 用户中心的服务名
spring:
  application:
    name: user-service
 
# 注册中心
eureka:
  instance:
    prefer-ip-address: true
    hostname: localhost
  client:
    service-url:
      defaultZone: http://localhost:8080/eureka/
 
# feign
feign:
  httpclient:
    enabled: true

@FeignClient(name = "user-service", fallback = UserServiceHystrix.class)
public interface UserService {
 
  @GetMapping("/user/getUserById")
  Result getUserById(@RequestParam("id") String id);
}

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface FeignClient {
  @AliasFor("name")
  String value() default "";
 
  
  @Deprecated
  String serviceId() default "";
 
  String contextId() default "";
 
  @AliasFor("value")
  String name() default "";
 
  String qualifier() default "";
 
  String url() default "";
 
  boolean decode404() default false;
 
  Class<?>[] configuration() default {};
 
  Class<?> fallback() default void.class;
 
  Class<?> fallbackFactory() default void.class;
 
  String path() default "";
 
  boolean primary() default true;
}

// 增加该配置时，该配置类就变成全局配置类
// @Configuration
public class FeignConfig implements RequestInterceptor {
 
  @Autowired
  private ObjectFactory<HttpMessageConverters> messageConverters;
 
  @Bean
  public Contract feignContract() {
    // feign 契约 @RequestLine
    return new Contract.Default();
    // springMVC契约 @GetMapping @PostMapping 等
    // return new SpringMvcContract();
  }
 
  // 记录请求和响应的头文件，正文和元数据的日志，需要在配置文件指出需要打印日志的类
  @Bean
  Logger.Level feignLoggerLevel() {
    return Logger.Level.FULL;
  }
 
  // 连接超时时间说明：连接超时时间，单位分钟，读取超时时间，单位秒，重定向为是
  @Bean
  public Options options() {
    return new Options(10, TimeUnit.MINUTES, 60, TimeUnit.SECONDS, true);
  }
 
  // 编码方式
  @Bean
  public Encoder feignFormEncoder() {
    return new SpringFormEncoder(new SpringEncoder(messageConverters));
  }
 
  // （全局设置）设置请求头等业务需要参数。
  @Override
  public void apply(RequestTemplate template) {
 
  }
}

server:
  port: 8080
 
#设置feign请求方式
feign:
  httpclient:
    enabled: true
 
# 打开debug请求日志 可以使用的参数有info warn error debug等
logging:
  level:
    com.example.feign.feign.ApiService: debug
 
# 第三方请求地址
api:
  url: https://api.apiopen.top

@FeignClient(value = "api-service", url = "${api.url}"
    , fallback = ApiServiceHystrix.class, configuration = FeignConfig.class)
public interface ApiService {
 
  
  @RequestLine("GET /getAllUrl")
  List<String> getAllUrl();
 
}

public class ApiServiceHystrix implements ApiService {
 
  @Override
  public List<String> getAllUrl() {
    // 设置调用失败时的降级处理
    return null;
  }
}

@Data
public class ApiResult implements Serializable {
 
  private static final long serialVersionUID = 1L;
 
  private Integer code;
 
  private String message;
 
  private List result;
 
}

  @RequestLine("POST /getImages?page={page}&count={count}")
  ApiResult getImages(@Param("page") String page, @Param("count") String count);

  @RequestLine("POST /deleteFeedback")
  ApiResult deleteFeedback(@RequestBody Map<String, ?> bodyMap);

  @RequestLine("POST /requestHeader")
  JSONObject getTcText(@HeaderMap Map<String, Object> headers, @RequestBody Map<String, Object> map);