默认的处理效果：
原理：ErrorMvcAutoConfiguration错误处理的自动配置
给容器添加了一下组件：
//ErrorAttributes,容器中没有这个组件则自动配置一个DefaultErrorAttributes，即我们看见的错误处理
@Bean
@ConditionalOnMissingBean(
value = {ErrorAttributes.class},
search = SearchStrategy.CURRENT
)
public DefaultErrorAttributes errorAttributes() {
return new DefaultErrorAttributes();
}
//ErrorController
@Bean
@ConditionalOnMissingBean(
value = {ErrorController.class},
search = SearchStrategy.CURRENT
)
public BasicErrorController basicErrorController(ErrorAttributes errorAttributes, ObjectProvider<ErrorViewResolver> errorViewResolvers) {
return new BasicErrorController(errorAttributes, this.serverProperties.getError(), (List)errorViewResolvers.orderedStream().collect(Collectors.toList()));
}
//ErrorPageCustomizer
@Bean
public ErrorMvcAutoConfiguration.ErrorPageCustomizer errorPageCustomizer(DispatcherServletPath dispatcherServletPath) {
return new ErrorMvcAutoConfiguration.ErrorPageCustomizer(this.serverProperties, dispatcherServletPath);
}
//DefaultErrorViewResolver
@Bean
@ConditionalOnBean({DispatcherServlet.class})
@ConditionalOnMissingBean({ErrorViewResolver.class})
DefaultErrorViewResolver conventionErrorViewResolver() {
return new DefaultErrorViewResolver(this.applicationContext, this.resourceProperties);
}
步骤：
? 一旦系统出现4xx或者5xx之类的错误，ErrorPageCustomizer就会生效（定制错误的响应规则），就会被BasicErrorController处理
? 响应页面：去哪个页面是由DefaultErrorViewResolver解析得到的;通过DefaultErrorAttributes获得错误页面可共享的信息：
? Status：状态码
? exception：异常对象
? message：异常消息
? error ：错误提示
? timestamp：时间戳
? errors：jsr303校验的错误
源码如下：
DefaultErrorAttributes
//帮我们在页面共享信息
public Map<String, Object> getErrorAttributes(WebRequest webRequest, ErrorAttributeOptions options) {
Map<String, Object> errorAttributes = this.getErrorAttributes(webRequest, options.isIncluded(Include.STACK_TRACE));
if (this.includeException != null) {
options = options.including(new Include[]{Include.EXCEPTION});
}
if (!options.isIncluded(Include.EXCEPTION)) {
errorAttributes.remove("exception");
}
if (!options.isIncluded(Include.STACK_TRACE)) {
errorAttributes.remove("trace");
}
if (!options.isIncluded(Include.MESSAGE) && errorAttributes.get("message") != null) {
errorAttributes.put("message", "");
}
if (!options.isIncluded(Include.BINDING_ERRORS)) {
errorAttributes.remove("errors");
}
return errorAttributes;
}
public Map<String, Object> getErrorAttributes(WebRequest webRequest, boolean includeStackTrace) {
Map<String, Object> errorAttributes = new LinkedHashMap();
errorAttributes.put("timestamp", new Date());
this.addStatus(errorAttributes, webRequest);
this.addErrorDetails(errorAttributes, webRequest, includeStackTrace);
this.addPath(errorAttributes, webRequest);
return errorAttributes;
}
BasicErrorController
@Controller
@RequestMapping({"${server.error.path:${error.path:/error}}"})
public class BasicErrorController extends AbstractErrorController {
//响应ErrorPageCustomizer发出的错误请求，${server.error.path:${error.path:/error}}如果有配置文件中配置路径，也能获取
//浏览器发送的请求请求头带有text/html，会来到这个方法处理
@RequestMapping(
produces = {"text/html"} //返回html格式
)
public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {
HttpStatus status = this.getStatus(request);
Map<String, Object> model = Collections.unmodifiableMap(this.getErrorAttributes(request, this.getErrorAttributeOptions(request, MediaType.TEXT_HTML)));
response.setStatus(status.value());
//ModelAndView ： 获得去往那个页面作为错误页面
ModelAndView modelAndView = this.resolveErrorView(request, response, status, model);
return modelAndView != null ? modelAndView : new ModelAndView("error", model);
}
//其他的设备请求头不会有text/html，就来到这个方法
@RequestMapping //ResponseEntity相应体力是map,list,javabean，输出格式也是json
public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
HttpStatus status = this.getStatus(request);
if (status == HttpStatus.NO_CONTENT) {
return new ResponseEntity(status);
} else {
Map<String, Object> body = this.getErrorAttributes(request, this.getErrorAttributeOptions(request, MediaType.ALL));
return new ResponseEntity(body, status);
}
}
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；
DefaultErrorViewResolver
protected ModelAndView resolveErrorView(HttpServletRequest request, HttpServletResponse response, HttpStatus status, Map<String, Object> model) {
Iterator var5 = this.errorViewResolvers.iterator();
ModelAndView modelAndView;
do {
if (!var5.hasNext()) {
return null;
}
//调用ErrorViewResolver获取所有错误页面，取到对应的就返回
ErrorViewResolver resolver = (ErrorViewResolver)var5.next();
modelAndView = resolver.resolveErrorView(request, status, model);
} while(modelAndView == null);
return modelAndView;
}
public ModelAndView resolveErrorView(HttpServletRequest request, HttpStatus status, Map<String, Object> model) {
ModelAndView modelAndView = this.resolve(String.valueOf(status.value()), model);
if (modelAndView == null && SERIES_VIEWS.containsKey(status.series())) {
modelAndView = this.resolve((String)SERIES_VIEWS.get(status.series()), model);
}
return modelAndView;
}
private ModelAndView resolve(String viewName, Map<String, Object> model) {
//默认SpringBoot可以去到一个页面？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
TemplateAvailabilityProvider provider = this.templateAvailabilityProviders.getProvider(errorViewName, this.applicationContext);
//模板引擎可用的情况下返回errorViewName指定的视图地址，不可用则在静态资源文件夹下找errorViewName页面
//error/404.html
return provider != null ? new ModelAndView(errorViewName, model) : this.resolveResource(errorViewName, model);
}
原文：https://www.cnblogs.com/JIATCODE/p/13169989.html