1、OpenFeign默认使用jdk自带的HttpURLConnection，HttpURLConnection没有连接池、性能和效率比较低
2、开启feign请求数据压缩时，大量的数据会导致json解析报错。例如：程序启动加载大量错误码到数据库时。

feign:
  # Feign请求响应压缩配置
  compression:
    request:
      # 开启Feign请求压缩，默认不开启
      enabled: true
      # 配置支持压缩的 MIME TYPE，默认为：text/xml,application/xml,application/json
      mime-types: text/xml,application/xml,application/json
      # 请求压缩阈值，超过此值才进行压缩，默认 2048 KB
      min-request-size: 2048
    response:
      # 开启Feign响应压缩，默认不开启
      enabled: true

报错如下：

org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Illegal character ((CTRL-CHAR, code 31)): only regular white space (\r, \n, \t) is allowed between tokens; nested exception is com.fasterxml.jackson.core.JsonParseException: Illegal character ((CTRL-CHAR, code 31)): only regular white space (\r, \n, \t) is allowed between tokens
 at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 2]
	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:391) ~[spring-web-5.3.31.jar:5.3.31]
	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:343) ~[spring-web-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:185) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:160) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:133) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:122) ~[spring-web-5.3.31.jar:5.3.31]
	at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:179) ~[spring-web-5.3.31.jar:5.3.31]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:146) ~[spring-web-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1072) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:965) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.31.jar:5.3.31]
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.3.31.jar:5.3.31]