Grails(Groovy)框架拋出NoHandlerFoundException而不是返回404 Not Found

本文記錄在基于Spring(Boot)框架（使用Java語言）和Grails框架（使用Groovy語言）下，開發Controller接口，對不存在的URL請求，接口返回404 not found，而不是拋出NoHandlerFoundException異常的問題，以及排查過程。

對于Spring (Boot)框架，請參考Spring 。

本文帶著對Grails的極大惡意，謹慎下翻。

Grails

對于Grails框架，使用Groovy開發的Controller接口，Postman請求不存在的index1接口，給出如下響應信息：
在這里插入圖片描述
切換到Preview：

經過分析，Postman上看到的preview頁面實際上是下圖中的notFound.gsp文件：

notFound.gsp文件如下：

<!doctype html>
<html><head><title>Page Not Found</title><meta name="layout" content="main"><g:if env="development"><asset:stylesheet src="errors.css"/></g:if></head><body><ul class="errors"><li>Error: Page Not Found (404)</li><li>Path: ${request.forwardURI}</li></ul></body>
</html>

gsp文件就是Grails下的JSP頁面，實際上是XML文件。

console打印日志：WARN [nio-8895-exec-5] o.s.web.servlet.PageNotFound : No mapping for GET /index1
在這里插入圖片描述
找不到這個類？？

NoHandlerFoundException

添加配置：

spring:mvc:throw-exception-if-no-handler-found: trueweb: # 必須關閉靜態資源的默認處理，否則 /health1 可能被靜態資源處理器攔截或跳過resources:add-mappings: false # 謹慎使用，可能影響靜態資源

報錯：
在這里插入圖片描述
Postman看到的還是上面的第二個圖。

添加配置類：

package com.abcd@Configuration
@EnableWebMvc
class NoHandlerConfig {@BeanServletRegistrationBean<DispatcherServlet> dispatcherServlet() {DispatcherServlet dispatcher = new DispatcherServlet()dispatcher.setThrowExceptionIfNoHandlerFound(true)  // 關鍵設置ServletRegistrationBean<DispatcherServlet> registration = new ServletRegistrationBean<>(dispatcher, "/")registration.setName("dispatcherServlet")return registration}
}

結果應用啟動報錯：

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.boot.actuate.autoconfigure.endpoint.web.CorsEndpointProperties' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}

注釋404映射：
在這里插入圖片描述

還是不行。

WTF？？

一個很簡單的技術需求，在Grails框架體系下實現起來怎么這么困難？？？

原理

Grails使用自己的UrlMappings路由系統，它基于AbstractController和動態調度。當訪問/health1：

Spring MVC層確實找不到Handler；
但Grails的NotFoundController或默認的grails.web.mapping.filter.UrlMappingFilter攔截請求；
最終返回404，根本不經過Spring的DispatcherServlet拋異常邏輯；
所以：NoHandlerFoundException根本不會被拋出，無論你怎么配置throwExceptionIfNoHandlerFound。

經過各種折騰，終于有了一個將就的解決方法：
在UrlMappings.groovy最后面添加如下配置：

"/*"(controller: 'notFound', action: 'handle')

再人工實現一個NotFoundController：

class NotFoundController {def handle() {throw new org.springframework.web.servlet.NoHandlerFoundException(request.method,request.forwardURI,new HttpHeaders())}
}

日志打印：

o.g.web.errors.GrailsExceptionResolver   : NoHandlerFoundException occurred when processing request: [GET] /health1
No handler found for GET /health1. Stacktrace follows: 
java.lang.reflect.InvocationTargetException: null
Caused by: org.springframework.web.servlet.NoHandlerFoundException: No handler found for GET /health1

Postman渲染HTML錯誤信息：
在這里插入圖片描述
上面代碼里寫的明明是new HttpHeaders()，這里卻變成String？？？事實上，這個參數類型變更的問題，我后來又遇到過一次。

這特么太搞笑了。

GlobalExceptionHandler

想要實現的效果是，GlobalExceptionHandler.groovy實現全局Controller接口接管。對于404 Not Found，使用ERROR級別來打印日志（忽視下面截圖里的錯誤，實際上應該是this.logError(e, "請求路徑不存在")）：
在這里插入圖片描述

UrlMappings.groovy

UrlMappings.groovy文件如下：

class UrlMappings {static mappings = {"/$controller/$action?/$id?(.$format)?" {constraints {// apply constraints here}}// 分組接口group "/doc", {"/"(controller: "document", method: "GET", action: "index") // 文檔列表"/$doc_id"(controller: "document", method: "GET", action: "detail") // 文檔詳情}// 單獨接口"/opts"(controller: "options", method: "GET", action: "index")// 省略其他若干"/"(view: "/index")"500"(view: '/error')"404"(view: '/notFound')}
}

刪除notFound.gsp文件（并沒有注釋UrlMappings文件里的404配置），請求/index1接口，報錯：

javax.servlet.ServletException: Could not resolve view with name '/notFound' in servlet with name 'grailsDispatcherServlet'
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1385) ~[spring-webmvc-5.3.33.jar:5.3.33]
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1150) ~[spring-webmvc-5.3.33.jar:5.3.33]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089) ~[spring-webmvc-5.3.33.jar:5.3.33]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:965) ~[spring-webmvc-5.3.33.jar:5.3.33]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.33.jar:5.3.33]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.33.jar:5.3.33]2024-12-31 14:00:57.501  --> ERROR [nio-8995-exec-4] o.a.c.c.C.[Tomcat].[localhost]           : Exception Processing ErrorPage[errorCode=404, location=/error]

PageNotFound

o.s.web.servlet.PageNotFound這個類到底是在哪個GAV里的？

這個類不存在，至少在spring-webmvc-5.x下面并不存在。

經過各種排查，

public class DispatcherServlet extends FrameworkServlet {public static final String PAGE_NOT_FOUND_LOG_CATEGORY = "org.springframework.web.servlet.PageNotFound";protected static final Log pageNotFoundLogger = LogFactory.getLog(PAGE_NOT_FOUND_LOG_CATEGORY);protected void noHandlerFound(HttpServletRequest request, HttpServletResponse response) throws Exception {if (pageNotFoundLogger.isWarnEnabled()) {pageNotFoundLogger.warn("No mapping for " + request.getMethod() + " " + getRequestUri(request));}if (this.throwExceptionIfNoHandlerFound) {throw new NoHandlerFoundException(request.getMethod(), getRequestUri(request),new ServletServerHttpRequest(request).getHeaders());} else {response.sendError(HttpServletResponse.SC_NOT_FOUND);}}protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {mappedHandler = getHandler(processedRequest);if (mappedHandler == null) {noHandlerFound(processedRequest, response);return;}}@Nullableprotected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {if (this.handlerMappings != null) {for (HandlerMapping mapping : this.handlerMappings) {HandlerExecutionChain handler = mapping.getHandler(request);if (handler != null) {return handler;}}}return null;}
}

在這里插入圖片描述
當Spring框架的DispatcherServlet無法找到處理請求的處理器（Handler）時，它會返回null，從而導致404 Not Found錯誤。

resources.groovy

resources.groovy文件如下：

import com.aliyun.oss.OSSClient
import io.minio.MinioAsyncClient
import io.minio.MinioClient// Place your Spring DSL code here
beans = {def grailsConfig = grailsApplication.configossClient(OSSClient, grailsConfig.oss?.endpoint, grailsConfig.oss?.accessKeyId, grailsConfig.oss?.accessKeySecret)minioClient(MinioClient, MinioAsyncClient.builder().endpoint(grailsConfig.minio?.endpoint as String).credentials(grailsConfig.minio?.accessKey as String, grailsConfig.minio?.secretKey as String).build())
}

增加：

import org.springframework.web.servlet.DispatcherServletbeans = {dispatcherServlet(DispatcherServlet) {throwExceptionIfNoHandlerFound = true}
}

結果報錯：
在這里插入圖片描述
console控制臺打印異常日志：

ERROR [nio-8867-exec-5] o.g.web.errors.GrailsExceptionResolver   : NullPointerException occurred when processing request: [GET] /temp/all
Stacktrace follows: 
java.lang.NullPointerException: nullat org.grails.web.mime.HttpServletResponseExtension.getMimeTypeForRequest(HttpServletResponseExtension.groovy:131) ~[grails-plugin-mimetypes-6.2.1.jar:6.2.1]at org.grails.web.mime.HttpServletResponseExtension.getMimeType(HttpServletResponseExtension.groovy:127) ~[grails-plugin-mimetypes-6.2.1.jar:6.2.1]at org.grails.web.mime.DefaultMimeTypeResolver.resolveResponseMimeType(DefaultMimeTypeResolver.groovy:41) ~[grails-plugin-mimetypes-6.2.1.jar:6.2.1]at org.grails.web.mapping.mvc.UrlMappingsHandlerMapping.findRequestedVersion(UrlMappingsHandlerMapping.groovy:184) ~[grails-web-url-mappings-6.2.1.jar:6.2.1]at org.grails.web.mapping.mvc.UrlMappingsHandlerMapping.getHandlerInternal(UrlMappingsHandlerMapping.groovy:132) ~[grails-web-url-mappings-6.2.1.jar:6.2.1]at org.springframework.web.servlet.handler.AbstractHandlerMapping.getHandler(AbstractHandlerMapping.java:499) ~[spring-webmvc-5.3.39.jar:5.3.39]at org.springframework.web.servlet.DispatcherServlet.getHandler(DispatcherServlet.java:1266) ~[spring-webmvc-5.3.39.jar:5.3.39]at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1048) ~[spring-webmvc-5.3.39.jar:5.3.39]ERROR [nio-8867-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.ClassCastException: class org.springframework.web.context.request.ServletRequestAttributes cannot be cast to class org.grails.web.servlet.mvc.GrailsWebRequest (org.springframework.web.context.request.ServletRequestAttributes and org.grails.web.servlet.mvc.GrailsWebRequest are in unnamed module of loader 'app')] with root cause 
java.lang.ClassCastException: class org.springframework.web.context.request.ServletRequestAttributes cannot be cast to class org.grails.web.servlet.mvc.GrailsWebRequest (org.springframework.web.context.request.ServletRequestAttributes and org.grails.web.servlet.mvc.GrailsWebRequest are in unnamed module of loader 'app')at org.grails.web.mapping.AbstractUrlMappingInfo.evaluateNameForValue(AbstractUrlMappingInfo.java:119) ~[grails-web-url-mappings-6.2.1.jar:6.2.1]at org.grails.web.mapping.DefaultUrlMappingInfo.getNamespace(DefaultUrlMappingInfo.java:185) ~[grails-web-url-mappings-6.2.1.jar:6.2.1]at org.grails.web.mapping.mvc.AbstractGrailsControllerUrlMappings.collectControllerMapping(AbstractGrailsControllerUrlMappings.groovy:206) ~[grails-web-url-mappings-6.2.1.jar:6.2.1]at org.grails.web.mapping.mvc.AbstractGrailsControllerUrlMappings.matchStatusCode(AbstractGrailsControllerUrlMappings.groovy:120) ~[grails-web-url-mappings-6.2.1.jar:6.2.1]WARN [nio-8867-exec-5] c.z.security.config.AdviceConfiguration  : [Web][有Warn被拋出] >> Warn類=[java.lang.IllegalArgumentException], URI=[/error], 消息=[不合法的參數異常], Warn=[java.lang.IllegalArgumentException: HandlerMapping requires a Grails web requestat org.springframework.util.Assert.notNull(Assert.java:201)at org.grails.web.mapping.mvc.UrlMappingsHandlerMapping.getHandlerInternal(UrlMappingsHandlerMapping.groovy:130)

應用啟動時，報錯如上面的StackTrace所示，后續的接口請求，則報錯StackTrace頂部的空指針：

ERROR [nio-8867-exec-9] c.z.security.config.AdviceConfiguration  : [Web][有異常被拋出] >> 異常類=[java.lang.NullPointerException], URI=[/temp/all], 消息=[null]

而且是所有的Controller接口都會報錯NPE！！！！

NPE

臭名昭著的空指針！為啥會NPE？？
在這里插入圖片描述
UrlMappingsHandlerMapping.groovy源碼：

@CompileStatic
class UrlMappingsHandlerMapping extends AbstractHandlerMapping {protected String findRequestedVersion(GrailsWebRequest currentRequest) {String version = currentRequest.getHeader(HttpHeaders.ACCEPT_VERSION)if(!version && mimeTypeResolver) {MimeType mimeType = mimeTypeResolver.resolveResponseMimeType(currentRequest)version = mimeType.version}return version}
}

DefaultMimeTypeResolver.groovy源碼：

@CompileStatic
class DefaultMimeTypeResolver implements MimeTypeResolver {@OverrideMimeType resolveResponseMimeType(GrailsWebRequest webRequest= GrailsWebRequest.lookup()) {if (webRequest != null) {return HttpServletResponseExtension.getMimeType(webRequest.response)}return null}
}

HttpServletResponseExtension.groovy源碼：

@CompileStatic
class HttpServletResponseExtension {@CompileStaticstatic MimeType getMimeType(HttpServletResponse response) {final webRequest = GrailsWebRequest.lookup()return getMimeTypeForRequest(webRequest)}private static MimeType getMimeTypeForRequest(GrailsWebRequest webRequest) {HttpServletRequest request = webRequest.getCurrentRequest()MimeType result = (MimeType) request.getAttribute(GrailsApplicationAttributes.RESPONSE_MIME_TYPE)if (!result) {// 省略代碼}return result}
}