Java实现自定义注解，实现不需要token 验证就可以访问接口

1 问题

一个springboot 项目，需要token 验证，前端传过来token ,我们一般在项目全局写一个过滤器，去验证前端传过来的token ,如果有哪些接口不需要token验证，那么就排除这些接口，这个也需要配置。

但是这样就有一个问题，那就是不能一直配置不需要token验证的接口

所以现在我们就需要自定义一个注解，如果你认为哪个接口不需要token 验证就可以访问，那么就在这个接口上面写这个自定义的注解就可以了

2 实现

第一步，自定义一个注解

/*** 排除token 注解* */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcludeTokenValidation {
}

第二步，写一个过滤器

@Slf4j
@Component
public class AuthInterceptor implements HandlerInterceptor {private static final String TOKEN = "token";@Autowiredprivate RedisUtil redisUtil;@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException {if (handler instanceof HandlerMethod) {HandlerMethod handlerMethod = (HandlerMethod) handler;// 检查方法上是否有 @ExcludeTokenValidation 注解if (handlerMethod.hasMethodAnnotation(ExcludeTokenValidation.class)) {return true; // 如果有该注解，直接通过，不进行 token 验证}}String token = request.getHeader(TOKEN);// 从参数中获取tokenif (ObjectUtils.isEmpty(token)) {token = request.getParameter(TOKEN);}if (!ObjectUtils.isEmpty(token)){SysUser loginUser = getUser(token);UserContext.setUser(loginUser);} else{response.setStatus(HttpServletResponse.SC_FORBIDDEN);output(response, noPermissionMsg("没有对应权限,联系管理员"));return false;}return true;}@Overridepublic void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {//手动清除当前用户上下文的用户对象UserContext.remove();}@Overridepublic void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {}/*** 获取用户信息* @param token* @return*/private SysUser getUser(String token) {Object o = redisUtil.get(token);JSONObject userJson = JSONObject.parseObject(o.toString());SysUser sysUser = JSON.toJavaObject(userJson, SysUser.class);return sysUser;}/*** 响应体返回** @param response* @param result* @throws IOException*/private void output(HttpServletResponse response, Result<String> result) throws IOException {response.setContentType("application/json;charset=UTF-8");ServletOutputStream outputStream = null;try {outputStream = response.getOutputStream();outputStream.write(JSON.toJSONString(result).getBytes(StandardCharsets.UTF_8));} catch (IOException e) {e.printStackTrace();} finally {outputStream.flush();outputStream.close();}}/*** @param msg 消息信息* @return Result<T> 统一返回*/private Result<String> noPermissionMsg(String msg) {String code = String.valueOf(HttpServletResponse.SC_FORBIDDEN);Result<String> stringResult = ResultUtil.build(code, msg, null);return stringResult;}}

第三步，全剧配置 这个 过滤器

@Configuration
public class WebConfig implements WebMvcConfigurer {@BeanAuthInterceptor authlInterceptor() {return new AuthInterceptor();}@Overridepublic void addInterceptors(InterceptorRegistry registry) {List<String> urls = new ArrayList<>();urls.add("/favicon.ico");urls.add("**/swagger-ui.html");urls.add("/swagger-ui.html/**");registry.addInterceptor(authlInterceptor()).addPathPatterns("/**").excludePathPatterns(urls);}
}

第四部，在不想要token 验证的接口上面添加这个自定义注解

第五步，启动项目之后，访问这个接口就可以了