一文吃透Spring Cloud gateway自定义错误处理Handler

public Mono handle(ServerWebExchange exchange, Throwable throwable) { // 判断response是否已经提交，并且调用isDisconnectedClientError方法判断是否是客户端断开连接。 // 如果已经断开连接,已经无法将消息发送给客户端，直接Mono.error(throwable)抛出异常。 if (!exchange.getResponse().isCommitted() && !this.isDisconnectedClientError(throwable)) { // exchange.getAttributes().putIfAbsent(ERROR_INTERNAL_ATTRIBUTE, error); this.errorAttributes.storeErrorInformation(throwable, exchange); // 创建request ServerRequest request = ServerRequest.create(exchange, this.messageReaders); return this.getRoutingFunction(this.errorAttributes).route(request).switchIfEmpty(Mono.error(throwable)).flatMap((handler) -> { return handler.handle(request); }).doOnNext((response) -> { this.logError(request, response, throwable); }).flatMap((response) -> { return this.write(exchange, response); }); } else { return Mono.error(throwable); } } 

private boolean isDisconnectedClientError(Throwable ex) { return DISCONNECTED_CLIENT_EXCEPTIONS.contains(ex.getClass().getSimpleName()) ||this.isDisconnectedClientErrorMessage(NestedExceptionUtils.getMostSpecificCause(ex).getMessage()); } 

private boolean isDisconnectedClientErrorMessage(String message) { message = message != null ? message.toLowerCase() : ""; return message.contains("broken pipe") || message.contains("connection reset by peer"); } 

public static Throwable getMostSpecificCause(Throwable ex) { Throwable cause; Throwable result = ex; while(null != (cause = result.getCause()) && (result != cause)) { result = cause; } return result; } 

protected void logError(ServerRequest request, ServerResponse response, Throwable throwable) { if (logger.isDebugEnabled()) { logger.debug(request.exchange().getLogPrefix() + this.formatError(throwable, request)); } if (HttpStatus.resolve(response.rawStatusCode()) != null && response.statusCode().equals(HttpStatus.INTERNAL_SERVER_ERROR)) { logger.error(LogMessage.of(() -> { return String.format("%s 500 Server Error for %s", request.exchange().getLogPrefix(), this.formatRequest(request)); }), throwable); } } 

private Mono write(ServerWebExchange exchange, ServerResponse response) { exchange.getResponse().getHeaders().setContentType(response.headers().getContentType()); return response.writeTo(exchange, new AbstractErrorWebExceptionHandler.ResponseContext()); } 

public void afterPropertiesSet() throws Exception { if (CollectionUtils.isEmpty(this.messageWriters)) { throw new IllegalArgumentException("Property 'messageWriters' is required"); } } 

protected Mono renderDefaultErrorView(BodyBuilder responseBody, Map error) { StringBuilder builder = new StringBuilder(); Date timestamp = (Date)error.get("timestamp"); Object message = error.get("message"); Object trace = error.get("trace"); Object requestId = error.get("requestId"); builder.append("
Whitelabel Error Page
").append("
This application has no configured error view, so you are seeing this as a fallback.
").append("
").append(timestamp).append("
").append("
[").append(requestId).append("] There was an unexpected error (type=").append(this.htmlEscape(error.get("error"))).append(", status=").append(this.htmlEscape(error.get("status"))).append(").
"); if (message != null) { builder.append("
").append(this.htmlEscape(message)).append("
"); } if (trace != null) { builder.append("
").append(this.htmlEscape(trace)).append("
"); } builder.append(""); return responseBody.bodyValue(builder.toString()); } 

protected Mono renderErrorView(String viewName, BodyBuilder responseBody, Map error) { if (this.isTemplateAvailable(viewName)) { return responseBody.render(viewName, error); } else { Resource resource = this.resolveResource(viewName); return resource != null ? responseBody.body(BodyInserters.fromResource(resource)) : Mono.empty(); } } 

private Resource resolveResource(String viewName) { // 获得所有的静态资源的路径 String[] var2 = this.resources.getStaticLocations(); int var3 = var2.length; // 遍历所有的静态资源 for(int var4 = 0; var4 

protected RouterFunction getRoutingFunction(ErrorAttributes errorAttributes) { return RouterFunctions.route(this.acceptsTextHtml(), this::renderErrorView).andRoute(RequestPredicates.all(), this::renderErrorResponse); } 

protected RequestPredicate acceptsTextHtml() { return (serverRequest) -> { try { // 获得请求头中的accept信息 List acceptedMediaTypes = serverRequest.headers().accept(); // 定义一个MediaType.ALL的MediaType对象 MediaType var10001 = MediaType.ALL; // 移除MediaType.ALL acceptedMediaTypes.removeIf(var10001::equalsTypeAndSubtype); // 根据类型和权重对MediaType进行排序 MediaType.sortBySpecificityAndQuality(acceptedMediaTypes); // 获得acceptMediaTypes的stream对象 Stream var10000 = acceptedMediaTypes.stream(); // 获得MediaType.TEXT_HTML的MediaType对象 var10001 = MediaType.TEXT_HTML; var10001.getClass(); // 判断是否有MediaType.TEXT_HTML return var10000.anyMatch(var10001::isCompatibleWith); } catch (InvalidMediaTypeException var2) { return false; } }; } 

protected Mono renderErrorView(ServerRequest request) { // 通过getErrorAttributes方法获得错误信息 Map error = this.getErrorAttributes(request, this.getErrorAttributeOptions(request, MediaType.TEXT_HTML)); // 获得错误状态码 int errorStatus = this.getHttpStatus(error); // 获得错误页面的模板名称 BodyBuilder responseBody = ServerResponse.status(errorStatus).contentType(TEXT_HTML_UTF8); // 获得错误页面的模板名称 return Flux.just(this.getData(errorStatus).toArray(new String[0])).flatMap((viewName) -> { return this.renderErrorView(viewName, responseBody, error); }).switchIfEmpty(this.errorProperties.getWhitelabel().isEnabled() ? this.renderDefaultErrorView(responseBody, error) : Mono.error(this.getError(request))).next(); } 

protected Mono renderErrorResponse(ServerRequest request) { // 通过getErrorAttributes方法获得错误信息 Map error = this.getErrorAttributes(request, this.getErrorAttributeOptions(request, MediaType.ALL)); // 获得错误状态码 // 设置为json格式的响应体 // 返回错误信息 return ServerResponse.status(this.getHttpStatus(error)).contentType(MediaType.APPLICATION_JSON).body(BodyInserters.fromValue(error)); } 

 protected ErrorAttributeOptions getErrorAttributeOptions(ServerRequest request, MediaType mediaType) { ErrorAttributeOptions options = ErrorAttributeOptions.defaults(); if (this.errorProperties.isIncludeException()) { options = options.including(new Include[]{Include.EXCEPTION}); } if (this.isIncludeStackTrace(request, mediaType)) { options = options.including(new Include[]{Include.STACK_TRACE}); } if (this.isIncludeMessage(request, mediaType)) { options = options.including(new Include[]{Include.MESSAGE}); } if (this.isIncludeBindingErrors(request, mediaType)) { options = options.including(new Include[]{Include.BINDING_ERRORS}); } return options; } 

import org.springframework.context.annotation.Configuration; @Configuration @Order(-1) public class MyErrorWebExceptionHandler extends DefaultErrorWebExceptionHandler { public MyErrorWebExceptionHandler(ErrorAttributes errorAttributes, ResourceProperties resourceProperties, ErrorProperties errorProperties, ApplicationContext applicationContext) { super(errorAttributes, resourceProperties, errorProperties, applicationContext); } @Override protected Map getErrorAttributes(ServerRequest request, ErrorAttributeOptions options) { Map errorAttributes = super.getErrorAttributes(request, options); errorAttributes.put("ext", "自定义异常处理类"); return errorAttributes; } } 

import org.springframework.context.annotation.Configuration; @Configuration @Order(-1) public class MyErrorWebExceptionHandler extends AbstractErrorWebExceptionHandler { public MyErrorWebExceptionHandler(ErrorAttributes errorAttributes, ResourceProperties resourceProperties, ErrorProperties errorProperties, ApplicationContext applicationContext) { super(errorAttributes, resourceProperties, errorProperties, applicationContext); } @Override protected RouterFunction getRoutingFunction(ErrorAttributes errorAttributes) { return RouterFunctions.route(RequestPredicates.all(), this::renderErrorResponse); } @Override protected Map getErrorAttributes(ServerRequest request, ErrorAttributeOptions options) { Map errorAttributes = super.getErrorAttributes(request, options); errorAttributes.put("ext", "自定义异常处理类"); return errorAttributes; } } 

import org.springframework.context.annotation.Configuration; @Configuration @Order(-1) public class MyErrorWebExceptionHandler implements WebExceptionHandler { @Override public Mono handle(ServerWebExchange exchange, Throwable ex) { ServerHttpResponse response = exchange.getResponse(); if (response.isCommitted()) { return Mono.error(ex); } else { response.getHeaders().setContentType(MediaType.APPLICATION_JSON); response.setStatusCode(HttpStatus.INTERNAL_SERVER_ERROR); return response.writeWith(Mono.just(response.bufferFactory().wrap("自定义异常处理类".getBytes()))); } } }