README.md

Springboot 获取 Header 参数

场景

• 在开发过程中，与前端交互的时候，基础信息(比如设备信息)会通过 Header 传递参数。需要拿到 header 中的参数做校验或者记录信息系。

获取 Header 参数方法

方法一

• 通过在类中注入 HttpServletRequest ，然后拿到 header

  @Autowired
  private HttpServletRequest httpServletRequest;
  
  @RequestMapping(value = "/printname/{name}", method = RequestMethod.GET)
  public String getHeader1(@PathVariable String name) {
      String token = httpServletRequest.getHeader("token");
      logger.debug("header:" + token + ", name:" + name);
      return "header-> token:" + token + ", name:" + name;
  }

方法二

• 在方法参数中加入@RequestHeader 获取到 header ，这种可以有两种获取方式。代码如下：

  @GetMapping(value = "/printname2/{name}")
  public String getHeader2(@PathVariable String name, @RequestHeader(value = "token") String token) {
      logger.debug("header:" + token + ", name:" + name);
      return "header-> token:" + token + ", name:" + name;
  }

  或者

  @GetMapping(value = "/printname3/{name}")
  public String getHeader3(@PathVariable String name, @RequestHeader HttpHeaders headers) {
      logger.debug("header:" + headers.getFirst("token") + ", name:" + name);
      logger.debug("header:" + headers.get("token").get(0) + ", name:" + name);
      return "header-> token:" + headers.getFirst("token") + ", name:" + name;
  }

方法三

• 自定义注解 + 自定义参数解析器 + 注册解析器
  1. 定义注解：RequestBodyAndHeader

     @Target(ElementType.PARAMETER)
     @Retention(RetentionPolicy.RUNTIME)
     @Documented
     public @interface RequestBodyAndHeader {
         boolean required() default true;
     }

  2. 定义注解解析器 RequestBodyAndHeaderResolver，继承 RequestResponseBodyMethodProcessor

     @Component
     public class RequestBodyAndHeaderResolver extends RequestResponseBodyMethodProcessor {
     
         public RequestBodyAndHeaderResolver(List<HttpMessageConverter<?>> converters) {
             super(converters);
         }
     
         @Override
         public boolean supportsParameter(MethodParameter parameter) {
             return parameter.hasParameterAnnotation(RequestBodyAndHeader.class);
         }
     
         @Override
         public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
             Object result = super.resolveArgument(parameter, mavContainer, webRequest, binderFactory);
             HashMap<String, String> headerParams = new HashMap<>(10);
             Iterator<String> headerNames = webRequest.getHeaderNames();
             headerNames.forEachRemaining(headerName -> headerParams.put(headerName, webRequest.getHeader(headerName)));
             BeanUtils.populate(result, headerParams);
             return result;
         }
     }

  3. 注册解析器：在配置类的 addArgumentResolvers 方法中注册解析器

     @Configuration
     public class WebConfig implements WebMvcConfigurer {
     
         @Autowired
         private RequestBodyAndHeaderResolver resolver;
     
         @Override
         public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
             resolvers.add(resolver);
         }
     }

注意： header 大小写不敏感，https://stackoverflow.com/questions/5258977/are-http-headers-case-sensitive。
参考： https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
参考： https://www.cnblogs.com/yuwentims/articles/9721953.html
参考： https://www.jianshu.com/p/bf59fbf5ccce