Feign 访问 400 时获取不到原始的错误信息

feign 客户端访问 api，拿到错误码（400、404、500...）时，默认会覆盖原本的错误信息，要获取原本的错误消息，可以写一个 ErrorDecoder 覆盖掉原本的默认实现：

import feign.Response;
import feign.codec.ErrorDecoder;
import io.undertow.util.BadRequestException;
import org.apache.ibatis.javassist.NotFoundException;
import org.springframework.stereotype.Component;

import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;

/**
 * <p> 2023/3/1 </p>
 * 拦截错误信息，将原本的错误信息返回
 *
 * @author Fqq
 */
@Component
public class RetreiveMessageErrorDecoder implements ErrorDecoder {
    private final ErrorDecoder errorDecoder = new Default();

    @Override
    public Exception decode(String methodKey, Response response) {
        String message;
        try (InputStream bodyIs = response.body().asInputStream()) {
            // 错误信息的 inputStream 转字符串
            message = new String(bodyIs.readAllBytes(), StandardCharsets.UTF_8);
        } catch (IOException e) {
            return new Exception(e.getMessage(), e);
        }
        switch (response.status()) {
            case 400:
                return new BadRequestException(message);
            case 404:
                return new NotFoundException("Not found");
            default:
                return errorDecoder.decode(methodKey, response);
        }
    }
}