根據不一樣的Accept,Whitelabel 會展示不一樣的representation:
(1)Accept:application/json
(2)Accept:text/html
(3)Accept:application/xml
html
w.s.m.s.DefaultHandlerExceptionResolver : Resolved exception caused by handler execution: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
Accept:text/html 時,api接口不存在時,後端會打印的錯誤日誌【這種大量打印錯誤日誌的行爲,會不會形成IO阻塞,並使服務器掛掉】:
spring webmvc的版本:5.0.9.RELEASE
java
2018-12-13 16:03:39.799 ERROR 14912 --- [nio-8080-exec-6] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] threw exception javax.servlet.ServletException: Circular view path [error]: would dispatch back to the current handler URL [/error] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view, due to default view name generation.) at org.springframework.web.servlet.view.InternalResourceView.prepareForRendering(InternalResourceView.java:209) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:147) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:315) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1325) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1069) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1008) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:728) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:472) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:395) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:316) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:395) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:254) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:177) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.34.jar:8.5.34] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_144] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_144] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.34.jar:8.5.34] at java.lang.Thread.run(Thread.java:748) [na:1.8.0_144] 2018-12-13 16:03:39.801 ERROR 14912 --- [nio-8080-exec-6] o.a.c.c.C.[Tomcat].[localhost] : Exception Processing ErrorPage[errorCode=0, location=/error] javax.servlet.ServletException: Circular view path [error]: would dispatch back to the current handler URL [/error] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view, due to default view name generation.) at org.springframework.web.servlet.view.InternalResourceView.prepareForRendering(InternalResourceView.java:209) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:147) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:315) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1325) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1069) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1008) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:728) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:472) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:395) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:316) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:395) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:254) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:177) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.34.jar:8.5.34] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_144] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_144] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.34.jar:8.5.34] at java.lang.Thread.run(Thread.java:748) [na:1.8.0_144]
Spring boot爲錯誤視圖提供了以下錯誤屬性:
timestamp:錯誤發生的時間
status:HTTP狀態碼
error:錯誤緣由
exception:異常的類名
message:異常消息(若是這個錯誤是由異常引發的)
errors:BindsResult異常裏的各類錯誤(若是這個錯誤是由異常引發的)
trace:異常跟蹤信息(若是這個錯誤是由異常引發的)
path:錯誤發生時請求的URL路徑web
test To switch it off you can set server.error.whitelabel.enabled=falsespring
錯誤問題會發生的,那些在生產環境裏最健壯的應用程序偶爾也會遇到麻煩。雖然減小用戶遇到錯誤的機率很重要,但讓應用程序展示一個好的錯誤頁面也一樣重要express
Spring Boot默認提供這個whitelabel錯誤頁,是自動配置的一部分。apache
Spring Boot自動配置的默認錯誤處理器會查找名爲error的視圖,若是找不到就用默認的whitelabel視圖。所以最簡單的方法就是建立一個自定義視圖,讓解析出的視圖名爲error
要達到預期的效果,須要有下面一項視圖解析器的配置:
(1)實現了Spring的View接口的Bean,其ID爲error(由Spring的BeanNameViewResolver所解析)
(2)若是配置了Thymeleaf,則有名爲error.html的Thymeleaf模板
(3)若是配置了FreeMarker,則有名爲error.ftl的FreeMarker模板
(4)若是配置了Velocity,則有名爲error.vm的Velocity模板
(5)若是是用JSP視圖,則有名爲error.jsp的JSP模板
固然視圖解析器要知道這個error的模板文件。
json
異常說明
SpringBoot搭建的接口服務,若是請求非註冊類的無效接口地址,則返回該頁面。主要問題就是沒有對異常請求作處理。後端
舉例,定義有效接口地址如:http://ip/user, http://ip/age。則其它地址均爲無效地址,若請求則返回上述Whitelabel Error Page頁面。api
2.0 異常處理tomcat
主要是添加一個AppErrorController的Controller類,這裏我定義了異常返回頁面。
import java.util.Map; import javax.servlet.http.HttpServletRequest; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.autoconfigure.web.ErrorAttributes; import org.springframework.boot.autoconfigure.web.ErrorController; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import org.springframework.web.context.request.RequestAttributes; import org.springframework.web.context.request.ServletRequestAttributes; import org.springframework.web.servlet.ModelAndView; @Controller public class AppErrorController implements ErrorController{ private static final Logger logger = LoggerFactory.getLogger(AppErrorController.class); private static AppErrorController appErrorController; /** * Error Attributes in the Application */ @Autowired private ErrorAttributes errorAttributes; private final static String ERROR_PATH = "/error"; /** * Controller for the Error Controller * @param errorAttributes * @return */ public AppErrorController(ErrorAttributes errorAttributes) { this.errorAttributes = errorAttributes; } public AppErrorController() { if(appErrorController == null){ appErrorController = new AppErrorController(errorAttributes); } } /** * Supports the HTML Error View * @param request * @return */ @RequestMapping(value = ERROR_PATH, produces = "text/html") public ModelAndView errorHtml(HttpServletRequest request) { return new ModelAndView("greeting", getErrorAttributes(request, false)); } /** * Supports other formats like JSON, XML * @param request * @return */ @RequestMapping(value = ERROR_PATH) @ResponseBody public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) { Map<String, Object> body = getErrorAttributes(request, getTraceParameter(request)); HttpStatus status = getStatus(request); return new ResponseEntity<Map<String, Object>>(body, status); } /** * Returns the path of the error page. * * @return the error path */ @Override public String getErrorPath() { return ERROR_PATH; } private boolean getTraceParameter(HttpServletRequest request) { String parameter = request.getParameter("trace"); if (parameter == null) { return false; } return !"false".equals(parameter.toLowerCase()); } private Map<String, Object> getErrorAttributes(HttpServletRequest request, boolean includeStackTrace) { RequestAttributes requestAttributes = new ServletRequestAttributes(request); Map<String, Object> map = this.errorAttributes.getErrorAttributes(requestAttributes,includeStackTrace); String URL = request.getRequestURL().toString(); map.put("URL", URL); logger.debug("AppErrorController.method [error info]: status-" + map.get("status") +", request url-" + URL); return map; } private HttpStatus getStatus(HttpServletRequest request) { Integer statusCode = (Integer) request .getAttribute("javax.servlet.error.status_code"); if (statusCode != null) { try { return HttpStatus.valueOf(statusCode); } catch (Exception ignored) { } } return HttpStatus.INTERNAL_SERVER_ERROR; } }
這個類實現了ErrorController接口,用來處理請求的各類異常。其中定義了一個greeting的html模版,用來顯示返回結果。
初始化此類模版須要在pom中加入如下依賴:
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency>
這個依賴主要是給SpringBoot中加載html等類型的模版服務。其支持的模版類型以下:
Template modes: [THYMELEAF] * XHTML [THYMELEAF] * XML [THYMELEAF] * HTML5 [THYMELEAF] * LEGACYHTML5 [THYMELEAF] * VALIDXHTML [THYMELEAF] * VALIDXML
org.thymeleaf.templatemode.TemplateMode
/* * ============================================================================= * * Copyright (c) 2011-2016, The THYMELEAF team (http://www.thymeleaf.org) * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * ============================================================================= */ package org.thymeleaf.templatemode; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.thymeleaf.TemplateEngine; import org.thymeleaf.templateresolver.AbstractConfigurableTemplateResolver; /** * * @author Daniel Fernández * * @since 3.0.0 * */ public enum TemplateMode { HTML(true, false, false), XML(false, true, false), TEXT(false, false, true), JAVASCRIPT(false, false, true), CSS(false, false, true), RAW(false, false, false), /** * Provided only for legacy compatibility reasons for old XML-based configurations (e.g. Spring). * <strong>Never</strong> use this value directly. Only to be used internally at * {@link AbstractConfigurableTemplateResolver} implementations. * * @deprecated Deprecated in 3.0.0. Use {@link #HTML} instead. Will be REMOVED in 3.1 */ @Deprecated HTML5(true, false, false), /** * Provided only for legacy compatibility reasons for old XML-based configurations (e.g. Spring). * <strong>Never</strong> use this value directly. Only to be used internally at * {@link AbstractConfigurableTemplateResolver} implementations. * * @deprecated Deprecated in 3.0.0. Use {@link #HTML} instead. Will be REMOVED in 3.1 */ @Deprecated LEGACYHTML5(true, false, false), /** * Provided only for legacy compatibility reasons for old XML-based configurations (e.g. Spring). * <strong>Never</strong> use this value directly. Only to be used internally at * {@link AbstractConfigurableTemplateResolver} implementations. * * @deprecated Deprecated in 3.0.0. Use {@link #HTML} instead. Will be REMOVED in 3.1 */ @Deprecated XHTML(true, false, false), /** * Provided only for legacy compatibility reasons for old XML-based configurations (e.g. Spring). * <strong>Never</strong> use this value directly. Only to be used internally at * {@link AbstractConfigurableTemplateResolver} implementations. * * @deprecated Deprecated in 3.0.0. Use {@link #HTML} instead. Will be REMOVED in 3.1 */ @Deprecated VALIDXHTML(true, false, false), /** * Provided only for legacy compatibility reasons for old XML-based configurations (e.g. Spring). * <strong>Never</strong> use this value directly. Only to be used internally at * {@link AbstractConfigurableTemplateResolver} implementations. * * @deprecated Deprecated in 3.0.0. Use {@link #XML} instead. Will be REMOVED in 3.1 */ @Deprecated VALIDXML(false, true, false); private static Logger logger = LoggerFactory.getLogger(TemplateMode.class); private final boolean html; private final boolean xml; private final boolean text; private final boolean caseSensitive; TemplateMode(final boolean html, final boolean xml, final boolean text) { this.html = html; this.xml = xml; this.text = text; this.caseSensitive = !this.html; } public boolean isMarkup() { return this.html || this.xml; } public boolean isText() { return this.text; } public boolean isCaseSensitive() { return this.caseSensitive; } public static TemplateMode parse(final String mode) { if (mode == null || mode.trim().length() == 0) { throw new IllegalArgumentException("Template mode cannot be null or empty"); } if ("HTML".equalsIgnoreCase(mode)) { return HTML; } if ("XML".equalsIgnoreCase(mode)) { return XML; } if ("TEXT".equalsIgnoreCase(mode)) { return TEXT; } if ("JAVASCRIPT".equalsIgnoreCase(mode)) { return JAVASCRIPT; } if ("CSS".equalsIgnoreCase(mode)) { return CSS; } if ("RAW".equalsIgnoreCase(mode)) { return RAW; } // Legacy template modes are automatically converted here // This code should probably be removed at some point in the distant future after Thymeleaf v3 if ("HTML5".equalsIgnoreCase(mode) || "XHTML".equalsIgnoreCase(mode) || "VALIDXHTML".equalsIgnoreCase(mode) || "LEGACYHTML5".equalsIgnoreCase(mode)) { logger.warn( "[THYMELEAF][{}] Template Mode '{}' is deprecated. Using Template Mode '{}' instead.", new Object[]{TemplateEngine.threadIndex(), mode, HTML}); return HTML; } if ("VALIDXML".equalsIgnoreCase(mode)) { logger.warn( "[THYMELEAF][{}] Template Mode '{}' is deprecated. Using Template Mode '{}' instead.", new Object[]{TemplateEngine.threadIndex(), mode, XML}); return XML; } logger.warn( "[THYMELEAF][{}] Unknown Template Mode '{}'. Must be one of: 'HTML', 'XML', 'TEXT', 'JAVASCRIPT', 'CSS', 'RAW'. " + "Using default Template Mode '{}'.", new Object[]{TemplateEngine.threadIndex(), mode, HTML}); return HTML; } }
SpringBoot項目配置模版路徑的方法以下:
一、在main的resources路徑下新建templates文件夾
二、在templates文件夾中新建模版文件greeting.html
<!DOCTYPE HTML> <html xmlns:th="http://www.thymeleaf.org"> <head> <title>Error Pages</title> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> </head> <body> <p th:text="'Url:' + ${URL}" /> <p th:text="'Error:' + ${error}" /> <p th:text="'Status:' + ${status}" /> <p th:text="'Timestamp:' + ${timestamp}" /> </body> </html>
3.0 處理結果
無效請求地址均會返回此頁面,只是其中的返回值不一樣。
Spring Boot Remove Whitelabel Error Page:
You need to change your code to the following:
@RestController public class IndexController implements ErrorController{ private static final String PATH = "/error"; @RequestMapping(value = PATH) public String error() { return "Error handling"; } @Override public String getErrorPath() { return PATH; } }
Your code did not work, because Spring Boot automatically registers the BasicErrorController as a Spring Bean when you have not specified an implementation of ErrorController.
To see that fact just navigate to ErrorMvcAutoConfiguration.basicErrorController
You can remove it completely by specifying:
import org.springframework.context.annotation.Configuration; import org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration; ... @Configuration @EnableAutoConfiguration(exclude = {ErrorMvcAutoConfiguration.class}) public static MainApp { ... }
However, do note that doing so will probably cause servlet container's whitelabel pages to show up instead :)
EDIT: Another way to do this is via application.yaml. Just put in the value:
spring:
autoconfigure:
exclude: org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration
https://stackoverflow.com/questions/25356781/spring-boot-remove-whitelabel-error-page