e.printStackTrace();
ServerHttpResponse response = exchange.getResponse();
JSONObject message = new JSONObject();
message.put("status", -1);
message.put("data", e.getMessage());
byte[] bits = message.toJSONString().getBytes(StandardCharsets.UTF_8);
DataBuffer buffer = response.bufferFactory().wrap(bits);
response.setStatusCode(HttpStatus.UNAUTHORIZED);
//指定編碼，否則在瀏覽器中會中文亂碼
response.getHeaders().add("Content-Type", "text/plain;charset=UTF-8");
return response.writeWith(Mono.just(buffer));

chain.filter(exchange);

 // 修改路徑
            String newPath ="/test/" + request.getPath();
            ServerHttpRequest newRequest = request.mutate()
                    .path(newPath)
                    .build();
            exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, newRequest.getURI());
            //放行
            return chain.filter(exchange.mutate()
                    .request(newRequest).build());

 routes:
        - id: token_routh
          uri: lb://test-service
          order: 0
          predicates:
            - Path=/test/**
          filters:
            # 去除/test
            - StripPrefix=1
            - TokenApi

public Mono<Void> handle(ServerWebExchange exchange) {
        if (logger.isDebugEnabled()) {
            ServerHttpRequest request = exchange.getRequest();
            logger.debug("Processing " + request.getMethodValue() + " request for [" + request.getURI() + "]");
        }
        //校驗handlerMapping集合是否為空
        //依次遍歷handlerMapping集合進行請求處理
        //通過mapping獲取mapping對應的handler，調用handler處理
        return this.handlerMappings == null ? Mono.error(HANDLER_NOT_FOUND_EXCEPTION) : Flux.fromIterable(this.handlerMappings).concatMap((mapping) -> {
            return mapping.getHandler(exchange);
        }).next().switchIfEmpty(Mono.error(HANDLER_NOT_FOUND_EXCEPTION)).flatMap((handler) -> {
            return this.invokeHandler(exchange, handler);
        }).flatMap((result) -> {
            return this.handleResult(exchange, result);
        });
    }

    public Mono<HandlerResult> handle(ServerWebExchange exchange, Object handler) {
        WebHandler webHandler = (WebHandler)handler;
        Mono<Void> mono = webHandler.handle(exchange);
        return mono.then(Mono.empty());
    }

public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
    private final FilteringWebHandler webHandler;
    private final RouteLocator routeLocator;
    public RoutePredicateHandlerMapping(FilteringWebHandler webHandler, RouteLocator routeLocator, GlobalCorsProperties globalCorsProperties) {
        this.webHandler = webHandler;
        this.routeLocator = routeLocator;
        //設置排序字段1，此處的目的是Spring Cloud Gateway 的 GatewayWebfluxEndpoint 提供 HTTP API ，不需要經(jīng)過網(wǎng)關
        //它通過 RequestMappingHandlerMapping 進行請求匹配處理。RequestMappingHandlerMapping 的 order = 0 ，
        // 需要排在 RoutePredicateHandlerMapping 前面。所有，RoutePredicateHandlerMapping 設置 order = 1 。
        this.setOrder(1);
        this.setCorsConfigurations(globalCorsProperties.getCorsConfigurations());
    }
    protected Mono<?> getHandlerInternal(ServerWebExchange exchange) {
        //設置mapping到上下文環(huán)境
        exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_HANDLER_MAPPER_ATTR, this.getClass().getSimpleName());
        // 查找路由
        return this.lookupRoute(exchange).flatMap((r) -> {
            exchange.getAttributes().remove(ServerWebExchangeUtils.GATEWAY_PREDICATE_ROUTE_ATTR);
            if (this.logger.isDebugEnabled()) {
                this.logger.debug("Mapping [" + this.getExchangeDesc(exchange) + "] to " + r);
            }
            //將找到的路由信息設置到上下文環(huán)境中
            exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR, r);
            //返回mapping對應的WebHandler即FilteringWebHandler
            return Mono.just(this.webHandler);
        }).switchIfEmpty(Mono.empty().then(Mono.fromRunnable(() -> {
            //當前未找到路由時返回空，并移除GATEWAY_PREDICATE_ROUTE_ATTR
            exchange.getAttributes().remove(ServerWebExchangeUtils.GATEWAY_PREDICATE_ROUTE_ATTR);
            if (this.logger.isTraceEnabled()) {
                this.logger.trace("No RouteDefinition found for [" + this.getExchangeDesc(exchange) + "]");
            }
        })));
    }
    protected CorsConfiguration getCorsConfiguration(Object handler, ServerWebExchange exchange) {
        return super.getCorsConfiguration(handler, exchange);
    }
    private String getExchangeDesc(ServerWebExchange exchange) {
        StringBuilder out = new StringBuilder();
        out.append("Exchange: ");
        out.append(exchange.getRequest().getMethod());
        out.append(" ");
        out.append(exchange.getRequest().getURI());
        return out.toString();
    }
    protected Mono<Route> lookupRoute(ServerWebExchange exchange) {
        //通過路由定位器獲取路由信息
        return this.routeLocator.getRoutes().concatMap((route) -> {
            return Mono.just(route).filterWhen((r) -> {
                exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_PREDICATE_ROUTE_ATTR, r.getId());
                return (Publisher)r.getPredicate().apply(exchange);
            }).doOnError((e) -> {
                this.logger.error("Error applying predicate for route: " + route.getId(), e);
            }).onErrorResume((e) -> {
                return Mono.empty();
            });
        }).next().map((route) -> {
            if (this.logger.isDebugEnabled()) {
                this.logger.debug("Route matched: " + route.getId());
            }
            this.validateRoute(route, exchange);
            return route;
        });
    }
    protected void validateRoute(Route route, ServerWebExchange exchange) {
    }
}

/**
 * 通過過濾器處理web請求的處理器
 */
public class FilteringWebHandler implements WebHandler {
    protected static final Log logger = LogFactory.getLog(FilteringWebHandler.class);
    /**
     * 全局過濾器
     */
    private final List<GatewayFilter> globalFilters;
    public FilteringWebHandler(List<GlobalFilter> globalFilters) {
        this.globalFilters = loadFilters(globalFilters);
    }
    /**
     * 包裝加載全局的過濾器，將全局過濾器包裝成GatewayFilter
     */
    private static List<GatewayFilter> loadFilters(List<GlobalFilter> filters) {
        return filters.stream()
                .map(filter -> {
                    //將所有的全局過濾器包裝成網(wǎng)關過濾器
                    GatewayFilterAdapter gatewayFilter = new GatewayFilterAdapter(filter);
                    //判斷全局過濾器是否實現(xiàn)了可排序接口
                    if (filter instanceof Ordered) {
                        int order = ((Ordered) filter).getOrder();
                        //包裝成可排序的網(wǎng)關過濾器
                        return new OrderedGatewayFilter(gatewayFilter, order);
                    }
                    return gatewayFilter;
                }).collect(Collectors.toList());
    }
    @Override
    public Mono<Void> handle(ServerWebExchange exchange) {
        //獲取請求上下文設置的路由實例
        Route route = exchange.getRequiredAttribute(GATEWAY_ROUTE_ATTR);
        //獲取路由定義下的網(wǎng)關過濾器集合
        List<GatewayFilter> gatewayFilters = route.getFilters();
        //組合全局的過濾器與路由配置的過濾器
        List<GatewayFilter> combined = new ArrayList<>(this.globalFilters);
        //添加路由配置過濾器到集合尾部
        combined.addAll(gatewayFilters);
        //對過濾器進行排序
        AnnotationAwareOrderComparator.sort(combined);
        logger.debug("Sorted gatewayFilterFactories: "+ combined);
        //創(chuàng)建過濾器鏈表對其進行鏈式調用
        return new DefaultGatewayFilterChain(combined).filter(exchange);
    }
}