标签：mapping 源码解析 type exception conf ext.get xtend message nal
默认效果：
1）、浏览器，返回一个默认的错误页面
1.1 请求头
1.2返回结果
2）、如果是其他客户端，默认响应一个json数据
2.1请求头
2.2返回结果
步骤：
1）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）；
2） 根据相应规则来到/error请求；被BasicErrorController处理；
3）响应页面；被Controller处理后去哪个页面是由DefaultErrorViewResolver解析得到的；
源码解析
public class ErrorMvcAutoConfiguration {
// 系统出现错误以后来到error请求进行处理；（相当于web.xml注册错误页面规则） @Bean public ErrorPageCustomizer errorPageCustomizer() { return new ErrorPageCustomizer(this.serverProperties, this.dispatcherServletPath); } /** * {@link WebServerFactoryCustomizer} that configures the server‘s error pages. */ private static class ErrorPageCustomizer implements ErrorPageRegistrar, Ordered { private final ServerProperties properties; private final DispatcherServletPath dispatcherServletPath; protected ErrorPageCustomizer(ServerProperties properties, DispatcherServletPath dispatcherServletPath) { this.properties = properties; this.dispatcherServletPath = dispatcherServletPath; } @Override public void registerErrorPages(ErrorPageRegistry errorPageRegistry) { ErrorPage errorPage = new ErrorPage(this.dispatcherServletPath .getRelativePath(this.properties.getError().getPath())); errorPageRegistry.addErrorPages(errorPage); } @Override public int getOrder() { return 0; } } } public class ErrorProperties { /** * Path of the error controller. */ @Value("${error.path:/error}") private String path = "/error"; }
public class ErrorMvcAutoConfiguration { // 系统出现错误以后来到error请求进行处理；（相当于web.xml注册错误页面规则） @Bean public ErrorPageCustomizer errorPageCustomizer() { return new ErrorPageCustomizer(this.serverProperties, this.dispatcherServletPath); } /** * {@link WebServerFactoryCustomizer} that configures the server‘s error pages. */ private static class ErrorPageCustomizer implements ErrorPageRegistrar, Ordered { private final ServerProperties properties; private final DispatcherServletPath dispatcherServletPath; protected ErrorPageCustomizer(ServerProperties properties, DispatcherServletPath dispatcherServletPath) { this.properties = properties; this.dispatcherServletPath = dispatcherServletPath; } @Override public void registerErrorPages(ErrorPageRegistry errorPageRegistry) { ErrorPage errorPage = new ErrorPage(this.dispatcherServletPath .getRelativePath(this.properties.getError().getPath())); errorPageRegistry.addErrorPages(errorPage); } @Override public int getOrder() { return 0; } } @Configuration @ConditionalOnProperty(prefix = "server.error.whitelabel", name = "enabled", matchIfMissing = true) @Conditional(ErrorTemplateMissingCondition.class) protected static class WhitelabelErrorViewConfiguration { //默认的SpringBoot错误页面 private final SpelView defaultErrorView = new SpelView( "<html><body><h1>Whitelabel Error Page</h1>" + "<p>This application has no explicit mapping for /error, so you are seeing this as a fallback.</p>" + "<div id=‘created‘>${timestamp}</div>" + "<div>There was an unexpected error (type=${error}, status=${status}).</div>" + "<div>${message}</div></body></html>"); @Bean(name = "error") @ConditionalOnMissingBean(name = "error") public View defaultErrorView() { return this.defaultErrorView; } // If the user adds @EnableWebMvc then the bean name view resolver from // WebMvcAutoConfiguration disappears, so add it back in to avoid disappointment. @Bean @ConditionalOnMissingBean public BeanNameViewResolver beanNameViewResolver() { BeanNameViewResolver resolver = new BeanNameViewResolver(); resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10); return resolver; } } } public class ErrorProperties { /** * Path of the error controller. */ @Value("${error.path:/error}") private String path = "/error"; }
public class ErrorMvcAutoConfiguration { @Bean @ConditionalOnMissingBean(value = ErrorController.class, search = SearchStrategy.CURRENT) public BasicErrorController basicErrorController(ErrorAttributes errorAttributes) { return new BasicErrorController(errorAttributes, this.serverProperties.getError(), this.errorViewResolvers); } } public abstract class AbstractErrorController implements ErrorController { private final ErrorAttributes errorAttributes; private final List<ErrorViewResolver> errorViewResolvers; public AbstractErrorController(ErrorAttributes errorAttributes) { this(errorAttributes, null); } //解析错误页面 protected ModelAndView resolveErrorView(HttpServletRequest request, HttpServletResponse response, HttpStatus status, Map<String, Object> model) { for (ErrorViewResolver resolver : this.errorViewResolvers) { ModelAndView modelAndView = resolver.resolveErrorView(request, status, model); if (modelAndView != null) { return modelAndView; } } return null; } } /**取出配置項：server.error.path中的值。如果沒有，則取error.path的值，如果還沒有，則默認為/error路徑*/ @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);
//如果为空，返回error视图（在ErrorMvcConfiguration中配置的@Bean） return (modelAndView != null) ? modelAndView : new ModelAndView("error", model); } //产生json数据，其他客户端来到这个方法处理； @RequestMapping @ResponseBody 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<>(body, status); } } public class DefaultErrorViewResolver implements ErrorViewResolver, Ordered { private static final Map<Series, String> SERIES_VIEWS;
private final ResourceProperties resourceProperties; static { Map<Series, String> views = new EnumMap<>(Series.class); views.put(Series.CLIENT_ERROR, "4xx"); views.put(Series.SERVER_ERROR, "5xx"); SERIES_VIEWS = Collections.unmodifiableMap(views); } @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 return resolveResource(errorViewName, model); } // private ModelAndView resolveResource(String viewName, Map<String, Object> model) {
//从静态资源文件夹下解析对应的页面 error/404.html for (String location : this.resourceProperties.getStaticLocations()) { try { Resource resource = this.applicationContext.getResource(location); resource = resource.createRelative(viewName + ".html"); if (resource.exists()) { return new ModelAndView(new HtmlResourceView(resource), model); } } catch (Exception ex) { } } return null; } }
静态资源文件夹路径
@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false) public class ResourceProperties { private static final String[] CLASSPATH_RESOURCE_LOCATIONS = { "classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/" }; /** * Locations of static resources. Defaults to classpath:[/META-INF/resources/, * /resources/, /static/, /public/]. */ private String[] staticLocations = CLASSPATH_RESOURCE_LOCATIONS; }
2）、如果定制错误响应
1、如何定制错误的页面
1）、有模板引擎的情况下；error/状态码; 【将错误页面命名为 错误状态码.html 放在模板引擎文件夹里面的error文件夹下】，发生此状态码的错误就会来到 对应的页面；
我们可以使用4xx和5xx作为错误页面的文件名来匹配这种类型的所有错误，精确优先（优先寻找精确的状态码.html）；
页面能获取的信息：
timestamp：时间戳
status：状态码
error：错误提示
exception：异常对象
message：异常消息
errors：JSR303数据校验的错误都在这里
2）、没有模板引擎（模板引擎找不到这个错误页面），静态资源文件夹下找
3）、以上都没有错误页面，就是默认来到SpringBoot默认的错误提示页面
2、如何定制错误的json数据；
1）、自定义异常处理&返回定制json数据；
标签：mapping 源码解析 type exception conf ext.get xtend message nal
原文地址：https://www.cnblogs.com/guchunchao/p/10011332.html
