Whitelabel Error Page 专题-白红宇

Spring boot为错误视图提供了如下错误属性：

timestamp：错误发生的时间

status：HTTP状态码

error：错误原因

exception：异常的类名

message：异常消息（如果这个错误是由异常引起的）

errors：BindsResult异常里的各种错误（如果这个错误是由异常引起的）

trace：异常跟踪信息（如果这个错误是由异常引起的）

path:错误发生时请求的URL路径

test To switch it off you can set server.error.whitelabel.enabled=false

错误问题会发生的，那些在生产环境里最健壮的应用程序偶尔也会遇到麻烦。虽然减少用户遇到错误的概率很重要，但让应用程序展现一个好的错误页面也同样重要

Spring Boot默认提供这个whitelabel错误页，是自动配置的一部分。

Spring Boot自动配置的默认错误处理器会查找名为error的视图，如果找不到就用默认的whitelabel视图。因此最简单的方法就是创建一个自定义视图，让解析出的视图名为error

要达到预期的效果，需要有下面一项视图解析器的配置：

（1）实现了Spring的View接口的Bean，其ID为error（由Spring的BeanNameViewResolver所解析）

（2）如果配置了Thymeleaf，则有名为error.html的Thymeleaf模板

（3）如果配置了FreeMarker，则有名为error.ftl的FreeMarker模板

（4）如果配置了Velocity，则有名为error.vm的Velocity模板

（5）如果是用JSP视图，则有名为error.jsp的JSP模板

当然视图解析器要知道这个error的模板文件。

异常说明

SpringBoot搭建的接口服务，如果请求非注册类的无效接口地址，则返回该页面。主要问题就是没有对异常请求做处理。

举例，定义有效接口地址如：http://ip/user, http://ip/age。则其它地址均为无效地址，若请求则返回上述Whitelabel Error Page页面。

2.0 异常处理

主要是添加一个AppErrorController的Controller类，这里我定义了异常返回页面。

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;@Controllerpublic 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
      
       > error(HttpServletRequest request) {        Map
       
         body = getErrorAttributes(request, getTraceParameter(request));        HttpStatus status = getStatus(request);        return new ResponseEntity
        
         
          >(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
          
            getErrorAttributes(HttpServletRequest request, boolean includeStackTrace) { RequestAttributes requestAttributes = new ServletRequestAttributes(request); Map
           
             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; } }

这个类实现了ErrorController接口，用来处理请求的各种异常。其中定义了一个greeting的html模版，用来显示返回结果。

初始化此类模版需要在pom中加入以下依赖：


                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-thymeleaf

这个依赖主要是给SpringBoot中加载html等类型的模版服务。其支持的模版类型如下：

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).     * Never 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).     * Never 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).     * Never 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).     * Never 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).     * Never 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项目配置模版路径的方法如下：

1、在main的resources路径下新建templates文件夹

2、在templates文件夹中新建模版文件greeting.html

Error Pages

3.0 处理结果

无效请求地址均会返回此页面，只是其中的返回值不同。