SpringBoot自定义错误处理机制（1-源码剖析）

比眉伴天荒 2022-05-24 11:37 197阅读 0赞

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## SpringBoot默认的错误处理页面 ##

可以参照ErrorMvcAutoConfiguration错误处理的自动配置：给容器中添加以下组件

### 1、**DefaultErrorAttributes** ###

@Override
            public Map<String, Object> getErrorAttributes(RequestAttributes requestAttributes,
            boolean includeStackTrace) {
                Map<String, Object> errorAttributes = new LinkedHashMap<String, Object>();
                errorAttributes.put("timestamp", new Date());
                addStatus(errorAttributes, requestAttributes);
                addErrorDetails(errorAttributes, requestAttributes, includeStackTrace);
                addPath(errorAttributes, requestAttributes);
                return errorAttributes;
            }

### **2、BasicErrorController：处理默认/error请求** ###

@Controller
    @RequestMapping("${server.error.path:${error.path:/error}}")
    public class BasicErrorController extends AbstractErrorController {
        @RequestMapping(produces = "text/html")//产生html类型的数据；浏览器发送的请求来到这个方法处理
        public ModelAndView errorHtml(HttpServletRequest request,
                                      HttpServletResponse response) {
            HttpStatus status = getStatus(request);
            Map<String, Object> model = Collections.unmodifiableMap(getErrorAttributes(
                    request, isIncludeStackTrace(request, MediaType.TEXT_HTML)));
            response.setStatus(status.value());
            //去哪个页面作为错误页面；包含页面地址和页面内容
            ModelAndView modelAndView = resolveErrorView(request, response, status, model);
            return (modelAndView == null ? new ModelAndView("error", model) : modelAndView);
        }
    
        @RequestMapping
        @ResponseBody //产生json数据，其他客户端来到这个方法处理；
        public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
            Map<String, Object> body = getErrorAttributes(request,
                    isIncludeStackTrace(request, MediaType.ALL));
            HttpStatus status = getStatus(request);
            return new ResponseEntity<Map<String, Object>>(body, status);
        }
    }

### **3、ErrorPageCustomizer** ###

###  ###

@Value("${error.path:/error}")
    private String path = "/error"; 系统出现错误以后来到error请求进行处理；（web.xml注册的错误页面规则）

### **4、DefaultErrorViewResolver** ###

@Override
            public ModelAndView resolveErrorView (HttpServletRequest request, HttpStatus status,Map< String, Object > model){
                ModelAndView modelAndView = resolve(String.valueOf(status), model);
                if (modelAndView == null && SERIES_VIEWS.containsKey(status.series())) {
                    modelAndView = resolve(SERIES_VIEWS.get(status.series()), model);
                }
                return modelAndView;
            }
            private ModelAndView resolve (String viewName, Map < String, Object > model){
                //默认SpringBoot可以去找到一个页面？ error/404
                String errorViewName = "error/" + viewName;
                //模板引擎可以解析这个页面地址就用模板引擎解析
                TemplateAvailabilityProvider provider = this.templateAvailabilityProviders
                        .getProvider(errorViewName, this.applicationContext);
                if (provider != null) {
                    //模板引擎可用的情况下返回到errorViewName指定的视图地址
                    return new ModelAndView(errorViewName, model);
                }
                //模板引擎不可用，就在静态资源文件夹下找errorViewName对应的页面 error/404.html
                return resolveResource(errorViewName, model);
            }

**步骤：单一系统出现的4xx或者5xx之类的错误：ErrorPageCustomizer就会生效，（定制错误的相应规则），就会来到/error请求，就会被BasicErrorController处理；**

去哪个页面是由DefaultErrorViewResolver得到的：

protected ModelAndView resolveErrorView(HttpServletRequest request,HttpServletResponse response, HttpStatus status,  
                 Map<String, Object> model) {
            //所有的ErrorViewResolver得到ModelAndView
            for (ErrorViewResolver resolver : this.errorViewResolvers) {
                ModelAndView modelAndView = resolver.resolveErrorView(request, status, model);
                if (modelAndView != null) {
                    return modelAndView;
                }
            }
            return null;
        }