起因：当调用get方法时，报错Could not extract response: no suitable HttpMessageConverter found for response type，解释就是无法序列化成Result，也就是返回值根本就不是一个json或者不是你需要的Result对象，通过对get2和get3方法的验证，发现get3方法返回值是一个500异常报错（也可以通过开启feign日志排查）

@FeignClient(value = "ai-agent-system",configuration = FeignConfiguration.class)
public interface SysUserServiceFeign {

    @GetMapping("/user/get")
    public Result<SysUserDO> get(String userId);

    @GetMapping("/user/get2")
    public SysUserDO get2(String userId);


    @GetMapping("/user/get3")
    public String get3(String userId);

}

解决：此处我的异常是因为在服务中需要token访问，也就是在请求头加上token，然后再次请求feign，OK！

添加过滤器

FeignConfiguration.class

@FeignClient(value = "ai-agent-system",configuration = FeignConfiguration.class)
public interface SysUserServiceFeign {

    @GetMapping("/user/get")
    public Result<SysUserDO> get(String userId);

    @GetMapping("/user/get2")
    public SysUserDO get2(String userId);


    @GetMapping("/user/get3")
    public String get3(@RequestParam("userId") String userId);

}

@Slf4j
@Configuration
public class FeignConfiguration implements RequestInterceptor{
    @Override
    public void apply(RequestTemplate requestTemplate) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        if(null != attributes) {
            HttpServletRequest request = attributes.getRequest();
            String token = request.getHeader("Authorization");
            log.info("token{}",token);
            requestTemplate.header(SaSameUtil.SAME_TOKEN, SaSameUtil.getToken());
        }
        log.info("feign interceptor header:{}",requestTemplate);
    }
}