单个参数

• 错误示例：下面示例中如果参数为空，不会报错，如果存在参数，会报错，因为OpenFeign在构造请求时需要@RequestMapping/@RequestParam/@PathVariable/@RequestHeader 等来构造http请求，而GET请求如果参数没有注解，会转为POST方式

  @FeignClient(name = "userFeignClient")
  public interface UserFeignClient {
      @RequestMapping(value = "/getInfo", method = RequestMethod.GET)
      public String getInfo(String name);
  }

• 正确写法

  @FeignClient(name = "userFeignClient")
  public interface UserFeignClient {
      @RequestMapping(value = "/getInfo", method = RequestMethod.GET)
      public String getInfo(@RequestParam("name") String name);
  }

多个参数

• 错误示例

  @FeignClient(name = "userFeignClient")
  public interface UserFeignClient {
      @RequestMapping(value = "/getInfo", method = RequestMethod.GET)
      public String getInfo(User user);
  }

• 正确写法一：使用 @SpringQueryMap

  @FeignClient(name = "userFeignClient")
  public interface UserFeignClient {
      @RequestMapping(value = "/getInfo", method = RequestMethod.GET)
      public String getInfo(@SpringQueryMap User user);
  }

• 正确写法二：将参数平铺，每个参数加上 @RequestParam 注解

  @FeignClient(name = "userFeignClient")
  public interface UserFeignClient {
      @RequestMapping(value = "/getInfo", method = RequestMethod.GET)
      public String getInfo(@RequestParam("name") String name, @RequestParam("age") Integer age);
  }

• 正确写法三：使用 Map + @RequestParam

  @FeignClient(name = "userFeignClient")
  public interface UserFeignClient {
      @RequestMapping(value = "/getInfo", method = RequestMethod.GET)
      public String getInfo(@RequestParam Map<String, Object> paramsMap);
  }