HttpServletRequest + Filter 添加 header

HttpServletRequest + Filter 添加 header

Filter 能够获得 HttpServletRequest 暴露的接口，但由于 HttpServletRequets 没有 setter方法，因此HttpServletRequest 是只可读的。但很多情况需要往HttpServletRequset 添加 header 参数，例如 token、userId。

1、自定义配置类

配置类继承 HttpServletRequestWrapper

public class CustomHttpServletRequest extends HttpServletRequestWrapper {private final Map<String, String> hashMap;/*** 初始化** @param request*/public CustomHttpServletRequest(HttpServletRequest request) {super(request);hashMap = new HashMap<>();}/*** 添加key、value** @param key* @param value*/public void addHeader(String key, String value) {hashMap.put(key, value);}/*** 获得value** @param key* @return*/@Overridepublic String getHeader(String key) {String value = super.getHeader(key);if (value == null) {value = hashMap.get(key);}return value;}/*** 获得value集合** @param key* @return*/@Overridepublic Enumeration<String> getHeaders(String key) {Enumeration<String> enumeration = super.getHeaders(key);List<String> valueList = Collections.list(enumeration);if (hashMap.containsKey(key)) {valueList.add(hashMap.get(key));}return Collections.enumeration(valueList);}/*** 获得key集合** @return*/@Overridepublic Enumeration<String> getHeaderNames(){List<String> keyList = Collections.list(super.getHeaderNames());keyList.addAll(hashMap.keySet());return Collections.enumeration(keyList);}}

2、Filter

Filter 调用配置类对象并添加 header

@WebFilter(filterName = \"AccessFilter\", urlPatterns = \"/*\")@Order(1)public class AccessFilter implements Filter {Logger logger = LoggerFactory.getLogger(AccessFilter.class);@Overridepublic void init(FilterConfig filterConfig) throws ServletException {}@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {HttpServletRequest request = (HttpServletRequest) servletRequest;CustomHttpServletRequest customHttpServletRequest = new CustomHttpServletRequest(request);//添加headercustomHttpServletRequest.addHeader(\"test\", \"123\");filterChain.doFilter(customHttpServletRequest, servletResponse);}@Overridepublic void destroy() {}

启动类添加

ServletComponentScan

注解

@MapperScan({\"com.lin.mapper\"})@SpringBootApplication@EnableTransactionManagement@ServletComponentScanpublic class MybatisPlusApplication {public static void main(String[] args) {SpringApplication.run(MybatisPlusApplication.class, args);}}

3、测试

调用接口进行测试

@GetMapping(value = \"/findById\")@ResponseBodypublic Result findById(@RequestParam(value = \"id\", required = true, defaultValue = \"2\") Long id,HttpServletRequest request) {User user = userService.findById(id);logger.info(\"===========\" + request.getHeader(\"test\") + \"==========\");return ResultUtil.success(user);}

打印出结果：

INFO 13880 --- [nio-8080-exec-2] com.lin.controller.UserController        : ===========123==========

总结：自定义配置类继承 HttpServletRequestWrapper，Filter 调用配置类并添加 header, 接口通过 getheader 方法获得已添加的 header。

参考资料：HttpServletRequest添加header