OpenFeignClient Use Object to Re

今日份鸡汤：你所做的事情，也许暂时看不到成果，但不要灰心或焦虑，你不是没有成长，而是在扎根~

首先看一下异常信息吧：

feign.codec.DecodeException: Could not extract response:
no suitable HttpMessageConverter found for response type [XXX.GlBaseResponse<XXX.model.UserDO>] and content type [text/html;charset=utf-8]

出现问题的场景：

使用FeignClient方式去调用公司其他团队同学提供的接口，并且返回值 使用泛型，例如 UserResponse<Model>。当请求参数正常的时候，接口返回里面的Content-Type：application/json;charset=UTF-8程序都能正常解析，而这个问题就是出现在当参数有误时，接口返回数据是JSON，而ContentType 为 text/html;charset=UTF-8，虽然吧，要是让人家更改也就一句话（header("ContentType", "application/json;charset=UTF-8");）就解决的事情，但是人家那边是不会为此做调整，所以，还是要自己用一些方法处理的。
这种HTTP协议不是很规范的情况下，可以通过配置Decoder来解决这个问题。

解决办法：

import feign.Logger;
import feign.codec.Decoder;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.cloud.openfeign.support.ResponseEntityDecoder;
import org.springframework.cloud.openfeign.support.SpringDecoder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;

import java.util.ArrayList;
import java.util.List;

@Configuration
public class FeignConfig {
    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }
    @Bean
    public Decoder feignDecoder() {
        return new ResponseEntityDecoder(new SpringDecoder(feignHttpMessageConverter()));
    }
    public ObjectFactory<HttpMessageConverters> feignHttpMessageConverter() {
        final HttpMessageConverters httpMessageConverters = new HttpMessageConverters(new Jackson2HttpMessageConverter());
        return new ObjectFactory<HttpMessageConverters>() {
            @Override
            public HttpMessageConverters getObject() throws BeansException {
                return httpMessageConverters;
            }
        };
    }
    public class Jackson2HttpMessageConverter  extends MappingJackson2HttpMessageConverter {
        Jackson2HttpMessageConverter(){
            List<MediaType> mediaTypes = new ArrayList<>();
            mediaTypes.add(MediaType.valueOf(MediaType.TEXT_HTML_VALUE + ";charset=UTF-8")); //关键
            setSupportedMediaTypes(mediaTypes);
        }
    }
}