Spring Cloud Gateway用于拦截并处理相关HTTP状态码

    AbstractErrorWebExceptionHandler 找到这个class 拿出来

    org.springframework.boot.autoconfigure.web.reactive.error

 package org.springframework.boot.autoconfigure.web.reactive.error;/* * Copyright 2012-2019 the original author or authors.
    
  * * 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
    
  * *      https://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.
    
  */
    
  
    
 import com.alibaba.fastjson.JSONObject;
    
 import lombok.extern.slf4j.Slf4j;
    
 import org.apache.commons.logging.Log;
    
 import org.springframework.beans.factory.InitializingBean;
    
 import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProviders;
    
 import org.springframework.boot.autoconfigure.web.ResourceProperties;
    
 import org.springframework.boot.web.reactive.error.ErrorAttributes;
    
 import org.springframework.boot.web.reactive.error.ErrorWebExceptionHandler;
    
 import org.springframework.context.ApplicationContext;
    
 import org.springframework.core.NestedExceptionUtils;
    
 import org.springframework.core.io.Resource;
    
 import org.springframework.core.io.buffer.DataBuffer;
    
 import org.springframework.http.HttpHeaders;
    
 import org.springframework.http.HttpLogging;
    
 import org.springframework.http.HttpStatus;
    
 import org.springframework.http.codec.HttpMessageReader;
    
 import org.springframework.http.codec.HttpMessageWriter;
    
 import org.springframework.http.server.reactive.ServerHttpResponse;
    
 import org.springframework.util.Assert;
    
 import org.springframework.util.CollectionUtils;
    
 import org.springframework.util.StringUtils;
    
 import org.springframework.web.reactive.function.BodyInserters;
    
 import org.springframework.web.reactive.function.server.RouterFunction;
    
 import org.springframework.web.reactive.function.server.ServerRequest;
    
 import org.springframework.web.reactive.function.server.ServerResponse;
    
 import org.springframework.web.reactive.result.view.ViewResolver;
    
 import org.springframework.web.server.ResponseStatusException;
    
 import org.springframework.web.server.ServerWebExchange;
    
 import org.springframework.web.util.HtmlUtils;
    
 import reactor.core.publisher.Mono;
    
  
    
 import java.nio.charset.StandardCharsets;
    
 import java.util.*;
    
  
    
 /** * Abstract base class for {@link ErrorWebExceptionHandler} implementations.
    
  * * @author Brian Clozel
    
  * @since 2.0.0
    
  * @see ErrorAttributes
    
  */
    
 @Slf4j
    
 public abstract class AbstractErrorWebExceptionHandler implements ErrorWebExceptionHandler, InitializingBean {
    
  
    
 	/** * Currently duplicated from Spring WebFlux HttpWebHandlerAdapter.
    
 	 */
    
 	private static final Set<String> DISCONNECTED_CLIENT_EXCEPTIONS;
    
  
    
 	static {
    
 		Set<String> exceptions = new HashSet<>();
    
 		exceptions.add("AbortedException");
    
 		exceptions.add("ClientAbortException");
    
 		exceptions.add("EOFException");
    
 		exceptions.add("EofException");
    
 		DISCONNECTED_CLIENT_EXCEPTIONS = Collections.unmodifiableSet(exceptions);
    
 	}
    
  
    
 	private static final Log logger = HttpLogging.forLogName(org.springframework.boot.autoconfigure.web.reactive.error.AbstractErrorWebExceptionHandler.class);
    
  
    
 	private final ApplicationContext applicationContext;
    
  
    
 	private final ErrorAttributes errorAttributes;
    
  
    
 	private final ResourceProperties resourceProperties;
    
  
    
 	private final TemplateAvailabilityProviders templateAvailabilityProviders;
    
  
    
 	private List<HttpMessageReader<?>> messageReaders = Collections.emptyList();
    
  
    
 	private List<HttpMessageWriter<?>> messageWriters = Collections.emptyList();
    
  
    
 	private List<ViewResolver> viewResolvers = Collections.emptyList();
    
  
    
 	public AbstractErrorWebExceptionHandler(ErrorAttributes errorAttributes, ResourceProperties resourceProperties,
    
                                         ApplicationContext applicationContext) {
    
 		Assert.notNull(errorAttributes, "ErrorAttributes must not be null");
    
 		Assert.notNull(resourceProperties, "ResourceProperties must not be null");
    
 		Assert.notNull(applicationContext, "ApplicationContext must not be null");
    
 		this.errorAttributes = errorAttributes;
    
 		this.resourceProperties = resourceProperties;
    
 		this.applicationContext = applicationContext;
    
 		this.templateAvailabilityProviders = new TemplateAvailabilityProviders(applicationContext);
    
 	}
    
  
    
 	/** * Configure HTTP message writers to serialize the response body with.
    
 	 * @param messageWriters the {@link HttpMessageWriter}s to use
    
 	 */
    
 	public void setMessageWriters(List<HttpMessageWriter<?>> messageWriters) {
    
 		Assert.notNull(messageWriters, "'messageWriters' must not be null");
    
 		this.messageWriters = messageWriters;
    
 	}
    
  
    
 	/** * Configure HTTP message readers to deserialize the request body with.
    
 	 * @param messageReaders the {@link HttpMessageReader}s to use
    
 	 */
    
 	public void setMessageReaders(List<HttpMessageReader<?>> messageReaders) {
    
 		Assert.notNull(messageReaders, "'messageReaders' must not be null");
    
 		this.messageReaders = messageReaders;
    
 	}
    
  
    
 	/** * Configure the {@link ViewResolver} to use for rendering views.
    
 	 * @param viewResolvers the list of {@link ViewResolver}s to use
    
 	 */
    
 	public void setViewResolvers(List<ViewResolver> viewResolvers) {
    
 		this.viewResolvers = viewResolvers;
    
 	}
    
  
    
 	/** * Extract the error attributes from the current request, to be used to populate error
    
 	 * views or JSON payloads.
    
 	 * @param request the source request
    
 	 * @param includeStackTrace whether to include the error stacktrace information
    
 	 * @return the error attributes as a Map.
    
 	 */
    
 	protected Map<String, Object> getErrorAttributes(ServerRequest request, boolean includeStackTrace) {
    
 		return this.errorAttributes.getErrorAttributes(request, includeStackTrace);
    
 	}
    
  
    
 	/** * Extract the original error from the current request.
    
 	 * @param request the source request
    
 	 * @return the error
    
 	 */
    
 	protected Throwable getError(ServerRequest request) {
    
 		return this.errorAttributes.getError(request);
    
 	}
    
  
    
 	/** * Check whether the trace attribute has been set on the given request.
    
 	 * @param request the source request
    
 	 * @return {@code true} if the error trace has been requested, {@code false} otherwise
    
 	 */
    
 	protected boolean isTraceEnabled(ServerRequest request) {
    
 		String parameter = request.queryParam("trace").orElse("false");
    
 		return !"false".equalsIgnoreCase(parameter);
    
 	}
    
  
    
 	/** * Render the given error data as a view, using a template view if available or a
    
 	 * static HTML file if available otherwise. This will return an empty
    
 	 * {@code Publisher} if none of the above are available.
    
 	 * @param viewName the view name
    
 	 * @param responseBody the error response being built
    
 	 * @param error the error data as a map
    
 	 * @return a Publisher of the {@link ServerResponse}
    
 	 */
    
 	protected Mono<ServerResponse> renderErrorView(String viewName, ServerResponse.BodyBuilder responseBody,
    
 			Map<String, Object> error) {
    
 		if (isTemplateAvailable(viewName)) {
    
 			return responseBody.render(viewName, error);
    
 		}
    
 		Resource resource = resolveResource(viewName);
    
 		if (resource != null) {
    
 			return responseBody.body(BodyInserters.fromResource(resource));
    
 		}
    
 		return Mono.empty();
    
 	}
    
  
    
 	private boolean isTemplateAvailable(String viewName) {
    
 		return this.templateAvailabilityProviders.getProvider(viewName, this.applicationContext) != null;
    
 	}
    
  
    
 	private Resource resolveResource(String viewName) {
    
 		for (String location : this.resourceProperties.getStaticLocations()) {
    
 			try {
    
 				Resource resource = this.applicationContext.getResource(location);
    
 				resource = resource.createRelative(viewName + ".html");
    
 				if (resource.exists()) {
    
 					return resource;
    
 				}
    
 			}
    
 			catch (Exception ex) {
    
 				// Ignore
    
 			}
    
 		}
    
 		return null;
    
 	}
    
  
    
 	/** * Render a default HTML "Whitelabel Error Page".
    
 	 * <p>
    
 	 * Useful when no other error view is available in the application.
    
 	 * @param responseBody the error response being built
    
 	 * @param error the error data as a map
    
 	 * @return a Publisher of the {@link ServerResponse}
    
 	 */
    
 	protected Mono<ServerResponse> renderDefaultErrorView(ServerResponse.BodyBuilder responseBody,
    
 			Map<String, Object> error) {
    
 		StringBuilder builder = new StringBuilder();
    
 		Date timestamp = (Date) error.get("timestamp");
    
 		Object message = error.get("message");
    
 		Object trace = error.get("trace");
    
 		builder.append("<html><body><h1>Whitelabel Error Page</h1>")
    
 				.append("<p>This application has no configured error view, so you are seeing this as a fallback.</p>")
    
 				.append("<div id='created'>").append(timestamp).append("</div>")
    
 				.append("<div>There was an unexpected error (type=").append(htmlEscape(error.get("error")))
    
 				.append(", status=").append(htmlEscape(error.get("status"))).append(").</div>");
    
 		if (message != null) {
    
 			builder.append("<div>").append(htmlEscape(message)).append("</div>");
    
 		}
    
 		if (trace != null) {
    
 			builder.append("<div style='white-space:pre-wrap;'>").append(htmlEscape(trace)).append("</div>");
    
 		}
    
 		builder.append("</body></html>");
    
 		return responseBody.syncBody(builder.toString());
    
 	}
    
  
    
 	private String htmlEscape(Object input) {
    
 		return (input != null) ? HtmlUtils.htmlEscape(input.toString()) : null;
    
 	}
    
  
    
 	@Override
    
 	public void afterPropertiesSet() throws Exception {
    
 		if (CollectionUtils.isEmpty(this.messageWriters)) {
    
 			throw new IllegalArgumentException("Property 'messageWriters' is required");
    
 		}
    
 	}
    
  
    
 	/** * Create a {@link RouterFunction} that can route and handle errors as JSON responses
    
 	 * or HTML views.
    
 	 * <p>
    
 	 * If the returned {@link RouterFunction} doesn't route to a {@code HandlerFunction},
    
 	 * the original exception is propagated in the pipeline and can be processed by other
    
 	 * {@link org.springframework.web.server.WebExceptionHandler}s.
    
 	 * @param errorAttributes the {@code ErrorAttributes} instance to use to extract error
    
 	 * information
    
 	 * @return a {@link RouterFunction} that routes and handles errors
    
 	 */
    
 	protected abstract RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes errorAttributes);
    
  
    
 	@Override
    
 	public Mono<Void> handle(ServerWebExchange exchange, Throwable throwable) {
    
 		if (exchange.getResponse().isCommitted() || isDisconnectedClientError(throwable)) {
    
 			return Mono.error(throwable);
    
 		}
    
 		this.errorAttributes.storeErrorInformation(throwable, exchange);
    
 		ServerRequest request = ServerRequest.create(exchange, this.messageReaders);
    
     if (throwable instanceof ResponseStatusException){
    
         HttpStatus status = ((ResponseStatusException) throwable).getStatus();
    
         if (HttpStatus.NOT_FOUND.equals(status)) {
    
           // TODO 处理你自己的业务
    
           // TODO 处理你自己的业务
    
         }
    
     }
    
     return getRoutingFunction(this.errorAttributes).route(request).switchIfEmpty(Mono.error(throwable))
    
 				.flatMap((handler) -> handler.handle(request))
    
 				.doOnNext((response) -> logError(request, response, throwable))
    
 				.flatMap((response) -> write(exchange, response));
    
 	}
    
  
    
 	private boolean isDisconnectedClientError(Throwable ex) {
    
 		return DISCONNECTED_CLIENT_EXCEPTIONS.contains(ex.getClass().getSimpleName())
    
 				|| 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"));
    
 	}
    
  
    
 	private void logError(ServerRequest request, ServerResponse response, Throwable throwable) {
    
 		if (logger.isDebugEnabled()) {
    
 			logger.debug(request.exchange().getLogPrefix() + formatError(throwable, request));
    
 		}
    
 		if (response.statusCode().equals(HttpStatus.INTERNAL_SERVER_ERROR)) {
    
 			logger.error(request.exchange().getLogPrefix() + "500 Server Error for " + formatRequest(request),
    
 					throwable);
    
 		}
    
 	}
    
  
    
 	private String formatError(Throwable ex, ServerRequest request) {
    
 		String reason = ex.getClass().getSimpleName() + ": " + ex.getMessage();
    
 		return "Resolved [" + reason + "] for HTTP " + request.methodName() + " " + request.path();
    
 	}
    
  
    
 	private String formatRequest(ServerRequest request) {
    
 		String rawQuery = request.uri().getRawQuery();
    
 		String query = StringUtils.hasText(rawQuery) ? "?" + rawQuery : "";
    
 		return "HTTP " + request.methodName() + " \"" + request.path() + query + "\"";
    
 	}
    
  
    
 	private Mono<? extends Void> write(ServerWebExchange exchange, ServerResponse response) {
    
 		// force content-type since writeTo won't overwrite response header values
    
 		exchange.getResponse().getHeaders().setContentType(response.headers().getContentType());
    
 		return response.writeTo(exchange, new ResponseContext());
    
 	}
    
  
    
 	private class ResponseContext implements ServerResponse.Context {
    
  
    
 		@Override
    
 		public List<HttpMessageWriter<?>> messageWriters() {
    
 			return org.springframework.boot.autoconfigure.web.reactive.error.AbstractErrorWebExceptionHandler.this.messageWriters;
    
 		}
    
  
    
 		@Override
    
 		public List<ViewResolver> viewResolvers() {
    
 			return org.springframework.boot.autoconfigure.web.reactive.error.AbstractErrorWebExceptionHandler.this.viewResolvers;
    
 		}
    
  
    
 	}
    
  
    
 }