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In this article, the editor introduces in detail "SpringBoot interceptor returns false to show how to solve cross-domain problems". The content is detailed, the steps are clear, and the details are handled properly. I hope this article "SpringBoot interceptor returns false to show how to solve cross-domain problems" can help you solve your doubts.

The project recently added a function of ip blacklist and whitelist. It is found that if the interceptor filtered by ip returns to false, the front end will show cross-domain. After trying to modify the MVC configuration class, it still won't work. Finally, add a judgment to the interceptor.

@ Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException {/ /-just add this-if (! (handler instanceof HandlerMethod)) {return true;}}

WebMvcConfigurer configuration class

@ Configuration@RestControllerAdvicepublic class WebMvcConfig implements WebMvcConfigurer {@ Resource private IpFilterInterceptor ipFilterInterceptor; @ Override public void addInterceptors (InterceptorRegistry registry) {/ / IP interceptor registry.addInterceptor (ipFilterInterceptor) .addPathPatterns ("/ *") .order (5) @ Override public void addCorsMappings (CorsRegistry registry) {registry.addMapping ("/ * *") .allowCredentials (true) .allowedOriginPatterns ("*") .allowedMethods ("*") .allowedHeaders ("*") .max Age (3600);}}

IP interceptor before modification

@ Componentpublic class IpFilterInterceptor implements HandlerInterceptor {/ * whether to enable * / private boolean enable; / * is whitelist * / private boolean isWhiteList; / * filter * / private List filters @ Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException {/ / disable if (! enable) {return true;} String ip = Servlets.getRemoteAddr (request); / / Native does not filter if (Const.LOCALHOST_IP_V4.equals (ip)) {return true } / / filter boolean contains = false; for (String filter: filters) {if (Strings.isBlank (filter)) {continue;} / / detect contains = Utils.checkIpIn (ip, filter); if (contains) {break }} / / result boolean pass; if (isWhiteList) {pass = contains;} else {pass =! contains;} / / returns if (! pass) {response.setContentType (StandardContentType.APPLICATION_JSON) Servlets.transfer (response, HttpWrapper.of (ResultCode.IP_BAN). ToJsonString (). GetBytes ());} return pass;}}

Modified IP interceptor

@ Componentpublic class IpFilterInterceptor implements HandlerInterceptor {/ * whether to enable * / private boolean enable; / * is whitelist * / private boolean isWhiteList; / * filter * / private List filters @ Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException {/ / disable if (! enable) {return true;} / /-just add this-if (! (handler instanceof HandlerMethod)) {return true } String ip = Servlets.getRemoteAddr (request); / / Native does not filter if (Const.LOCALHOST_IP_V4.equals (ip)) {return true;} / / filter boolean contains = false; for (String filter: filters) {if (Strings.isBlank (filter)) {continue } / / detect contains = Utils.checkIpIn (ip, filter); if (contains) {break;}} / / result boolean pass; if (isWhiteList) {pass = contains;} else {pass =! contains } / / return if (! pass) {response.setContentType (StandardContentType.APPLICATION_JSON); Servlets.transfer (response, HttpWrapper.of (ResultCode.IP_BAN). ToJsonString (). GetBytes ();} return pass;}}

Finally, the reason for the problem is that the interceptor needs to determine in preHandle that the handler type must be HandlerMethod in order to pass.

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