Feign 基础数据操作

## 表单form传参
1. 使用@RequestBody传参
2. consumes指定为application/x-www-form-urlencoded
3. 注入一个form编码器，实现支持form表单提交

参考代码

```
@FeignClient(name = "beyondtime-io-kc-client", url = "${btio.keycloakUrl}", path = "/", configuration = KeycloakAdminClient.Configuration.class)
public interface KeycloakAdminClient {

@PostMapping(value="realms/master/protocol/openid-connect/token", consumes = MediaType.APPLICATION_FROM_URLENCODED_VALUE)
    KeycloakAccessToken getAuthToken(@RequestBody AuthTokenRequest authTokenRequest);

class Configuration {
        @Bean
        Encoder feignFormEncoder(ObjectFactory<HttpMessageConverters> converters) {
            return new SpringFormEncoder(new SpringEncoder(converters));
        }
    }
}
```

原文：https://www.coder.work/article/6184670

## get请求用对象传参
1. 使用@SpringQueryMap标识对象
```
@FeignClient(name = "beyondtime-io-kc-client", url = "${btio.keycloakUrl}", path = "/")
public interface KeycloakAdminClient {
	@GetMapping(value = "/foo")
	String foo(@SpringQueryMap Request params);
}
```
2. 入参有别名的使用@Param，而不是@JsonProperty
```
@Data
public class Request {
    // @Param可以为参数设置别名,以适配不符合编码规范的参数名
    @Param("userid")
    private String userId;

private String app;
}
```
3. 将FieldQueryMapEncoder注册为bean
```
@Configuration
public class Configuration {
	@Bean
	public QueryMapEncoder feignQueryMapEncoder(){
		return new FieldQueryMapEncoder();
	}
}
```

## 更改feign的打印级别
```yml
logging:
  level:
    com.maybecare: debug

feign:
  client:
    config:
      # feign全局日志级别
      default:
        loggerLevel: full
```

## 取消HTTPS的SSL验证
```
@Configuration
public class FeignConfiguration {

@Bean
    public CachingSpringLoadBalancerFactory cachingFactory(SpringClientFactory clientFactory) {
        return new CachingSpringLoadBalancerFactory(clientFactory);
    }

@Bean
    @ConditionalOnMissingBean
    public Client feignClient(CachingSpringLoadBalancerFactory cachingFactory,
                              SpringClientFactory clientFactory) throws NoSuchAlgorithmException, KeyManagementException {
        SSLContext ctx = SSLContext.getInstance("SSL");
        X509TrustManager tm = new X509TrustManager() {
            @Override
            public void checkClientTrusted(X509Certificate[] chain, String authType) {
            }
            @Override
            public void checkServerTrusted(X509Certificate[] chain, String authType) {
            }
            @Override
            public X509Certificate[] getAcceptedIssuers() {
                return null;
            }
        };
        ctx.init(null, new TrustManager[]{tm}, null);
        return new LoadBalancerFeignClient(new Client.Default(ctx.getSocketFactory(),
                (hostname, session) -> true),
                cachingFactory, clientFactory);
    }
}

// 原文链接：https://blog.csdn.net/u010670568/article/details/119662310
```

## feign流式下载大文件
1. feign 定义
```
@FeignClient(name = "streamFileGet", path = "/")
public interface FileClient {
	@GetMapping(value = "/file/get")
	Response getFile(@RequestParam String filename);
}
```
2. 使用流式读取
```
public class FileService{
	public void fileGet() {
		Response response = fileClient.getFile("demo.txt");
		try(InputStream reader = response.body().asInputStream()) {
			String row;
			BufferedReader buffReader = new BufferedReader(new InputStreamReader(reader, "UTF-8"))
			while((row = buffReader.readLine() != null)) {
				doSomething(row);
			}
		} catch(Exception e) {
			log.error("流式解析异常",e);
		}
	}
}
```

## feign 转发请求头保证登录等
```

@Slf4j
@Configuration
public class FeignConfiguration implements RequestInterceptor {
  @Override
  public void apply(RequestTemplate requestTemplate) {
    // 1.从前端过来的请求头取信息
    RequestAttributes reqAttributes = RequestContextHolder.currentRequestAttributes();
    HttpServletRequest request = ((ServletRequestAttributes) reqAttributes).getRequest();
    String cityCode = request.getHeader("cityCode");
    requestTemplate.header("cityCode", cityCode);
    // 2.设置自定义请求头信息
    requestTemplate.header("cityNo", "0571");
  }

```
https://blog.csdn.net/zhangbeizhen18/article/details/129760458