在使用zuul的时候遇到的坑总结一下：
逐渐增加更新以后遇到的
1、在路由的时候莫名其妙的把serviceId给去掉，导致404。比如请求：/serviceId/search/book，zuul会把serviceId去掉，导致匹配不到服务404
解决办法:
zuul:
strip-prefix: false

因为我们没有设置zuul.prefix 为所有的匹配增加前缀, 例如 /api,代理前缀默认会从请求路径中移除(通过 zuul.stripPrefix=false 可以关闭这个功能)

当stripPrefix=true的时候 （http://127.0.0.1:8181/api/user/list -> http://192.168.1.100:8080/user/list）

当stripPrefix=false的时候（http://127.0.0.1:8181/api/user/list -> http://192.168.1.100:8080/api/user/list）

设置这个值以后还是出现了404的问题。最后只能自己实现路由映射。
自定义路由：https://www.jianshu.com/p/647cf467b47c
2、在zuul的过滤器中，有一个FormBodyWrapperFilter过滤器，在使用resin做web容器时启动会报 ServletRequestWrapper.request field not found
通过跟踪源码发现resin的ServletRequestWrapper种的request会多一个下划线，导致

this.servletRequestField = ReflectionUtils.findField(ServletRequestWrapper.class,
                "request", ServletRequest.class);

找不到servletRequestField。
解决办法：
重写ZuulServerAutoConfiguration这个类并注释掉FormBodyWrapperFilter的bean

/*
 * Copyright 2013-2017 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
 *
 *      http://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.
 */

package org.springframework.cloud.netflix.zuul;

import com.netflix.zuul.FilterLoader;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.filters.FilterRegistry;
import com.netflix.zuul.http.ZuulServlet;
import com.netflix.zuul.monitoring.CounterFactory;
import com.netflix.zuul.monitoring.TracerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.actuate.metrics.CounterService;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.web.ErrorController;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.cloud.client.actuator.HasFeatures;
import org.springframework.cloud.client.discovery.event.HeartbeatEvent;
import org.springframework.cloud.client.discovery.event.HeartbeatMonitor;
import org.springframework.cloud.context.scope.refresh.RefreshScopeRefreshedEvent;
import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
import org.springframework.cloud.netflix.zuul.filters.CompositeRouteLocator;
import org.springframework.cloud.netflix.zuul.filters.RouteLocator;
import org.springframework.cloud.netflix.zuul.filters.SimpleRouteLocator;
import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
import org.springframework.cloud.netflix.zuul.filters.post.SendErrorFilter;
import org.springframework.cloud.netflix.zuul.filters.post.SendResponseFilter;
import org.springframework.cloud.netflix.zuul.filters.pre.DebugFilter;
import org.springframework.cloud.netflix.zuul.filters.pre.Servlet30WrapperFilter;
import org.springframework.cloud.netflix.zuul.filters.pre.ServletDetectionFilter;
import org.springframework.cloud.netflix.zuul.filters.route.SendForwardFilter;
import org.springframework.cloud.netflix.zuul.metrics.DefaultCounterFactory;
import org.springframework.cloud.netflix.zuul.metrics.EmptyCounterFactory;
import org.springframework.cloud.netflix.zuul.metrics.EmptyTracerFactory;
import org.springframework.cloud.netflix.zuul.web.ZuulController;
import org.springframework.cloud.netflix.zuul.web.ZuulHandlerMapping;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.Primary;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.core.annotation.Order;

import java.util.Collection;
import java.util.Map;

/**
 * @author Spencer Gibb
 * @author Dave Syer
 * @author Biju Kunjummen
 */
@Configuration
@EnableConfigurationProperties({ZuulProperties.class})
@ConditionalOnClass(ZuulServlet.class)
@ConditionalOnBean(ZuulServerMarkerConfiguration.Marker.class)
// Make sure to get the ServerProperties from the same place as a normal web app would
@Import(ServerPropertiesAutoConfiguration.class)
public class ZuulServerAutoConfiguration {

    @Autowired
    protected ZuulProperties zuulProperties;

    @Autowired
    protected ServerProperties server;

    @Autowired(required = false)
    private ErrorController errorController;

    @Bean
    public HasFeatures zuulFeature() {
        return HasFeatures.namedFeature("Zuul (Simple)", ZuulServerAutoConfiguration.class);
    }

    @Bean
    @Primary
    public CompositeRouteLocator primaryRouteLocator(
            Collection<RouteLocator> routeLocators) {
        return new CompositeRouteLocator(routeLocators);
    }

    @Bean
    @ConditionalOnMissingBean(SimpleRouteLocator.class)
    public SimpleRouteLocator simpleRouteLocator() {
        return new SimpleRouteLocator(this.server.getServletPrefix(),
                this.zuulProperties);
    }

    @Bean
    public ZuulController zuulController() {
        return new ZuulController();
    }

    @Bean
    public ZuulHandlerMapping zuulHandlerMapping(RouteLocator routes) {
        ZuulHandlerMapping mapping = new ZuulHandlerMapping(routes, zuulController());
        mapping.setErrorController(this.errorController);
        return mapping;
    }

    @Bean
    public ApplicationListener<ApplicationEvent> zuulRefreshRoutesListener() {
        return new ZuulRefreshListener();
    }

    @Bean
    @ConditionalOnMissingBean(name = "zuulServlet")
    public ServletRegistrationBean zuulServlet() {
        ServletRegistrationBean servlet = new ServletRegistrationBean(new ZuulServlet(),
                this.zuulProperties.getServletPattern());
        // The whole point of exposing this servlet is to provide a route that doesn't
        // buffer requests.
        servlet.addInitParameter("buffer-requests", "false");
        return servlet;
    }

    // pre filters

    @Bean
    public ServletDetectionFilter servletDetectionFilter() {
        return new ServletDetectionFilter();
    }

//    @Bean
//    public FormBodyWrapperFilter formBodyWrapperFilter() {
//        return new FormBodyWrapperFilter();
//    }

    @Bean
    public DebugFilter debugFilter() {
        return new DebugFilter();
    }

    @Bean
    public Servlet30WrapperFilter servlet30WrapperFilter() {
        return new Servlet30WrapperFilter();
    }

    // post filters

    @Bean
    public SendResponseFilter sendResponseFilter() {
        return new SendResponseFilter();
    }

    @Bean
    public SendErrorFilter sendErrorFilter() {
        return new SendErrorFilter();
    }

    @Bean
    public SendForwardFilter sendForwardFilter() {
        return new SendForwardFilter();
    }

    @Bean
    @ConditionalOnProperty(value = "zuul.ribbon.eager-load.enabled", matchIfMissing = false)
    public ZuulRouteApplicationContextInitializer zuulRoutesApplicationContextInitiazer(
            SpringClientFactory springClientFactory) {
        return new ZuulRouteApplicationContextInitializer(springClientFactory,
                zuulProperties);
    }

    @Configuration
    protected static class ZuulFilterConfiguration {

        @Autowired
        private Map<String, ZuulFilter> filters;

        @Bean
        public ZuulFilterInitializer zuulFilterInitializer(
                CounterFactory counterFactory, TracerFactory tracerFactory) {
            FilterLoader filterLoader = FilterLoader.getInstance();
            FilterRegistry filterRegistry = FilterRegistry.instance();
            return new ZuulFilterInitializer(this.filters, counterFactory, tracerFactory, filterLoader, filterRegistry);
        }

    }

    @Configuration
    @ConditionalOnClass(CounterService.class)
    protected static class ZuulCounterFactoryConfiguration {

        @Bean
        @ConditionalOnBean(CounterService.class)
        public CounterFactory counterFactory(CounterService counterService) {
            return new DefaultCounterFactory(counterService);
        }
    }

    @Configuration
    protected static class ZuulMetricsConfiguration {

        @Bean
        @ConditionalOnMissingBean(CounterFactory.class)
        public CounterFactory counterFactory() {
            return new EmptyCounterFactory();
        }

        @ConditionalOnMissingBean(TracerFactory.class)
        @Bean
        public TracerFactory tracerFactory() {
            return new EmptyTracerFactory();
        }

    }

    private static class ZuulRefreshListener
            implements ApplicationListener<ApplicationEvent> {

        @Autowired
        private ZuulHandlerMapping zuulHandlerMapping;

        private HeartbeatMonitor heartbeatMonitor = new HeartbeatMonitor();

        @Override
        public void onApplicationEvent(ApplicationEvent event) {
            if (event instanceof ContextRefreshedEvent
                    || event instanceof RefreshScopeRefreshedEvent
                    || event instanceof RoutesRefreshedEvent) {
                this.zuulHandlerMapping.setDirty(true);
            } else if (event instanceof HeartbeatEvent) {
                if (this.heartbeatMonitor.update(((HeartbeatEvent) event).getValue())) {
                    this.zuulHandlerMapping.setDirty(true);
                }
            }
        }

    }

}