Zuul将请求通过外部代理服务器进行路由。

以下是一个使用 Zuul 进行请求转发的示例代码：

首先，需要在项目的依赖中添加 Spring Cloud Zuul 的依赖，例如在 Maven 中：

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
</dependency>

然后，在 Spring Boot 的启动类上添加 @EnableZuulProxy 注解，启用 Zuul 代理功能：

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableZuulProxy
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

接下来，创建一个 Zuul 配置类，用于配置路由规则：

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.cloud.netflix.zuul.ZuulFilter;
import org.springframework.cloud.netflix.zuul.filters.RouteLocator;
import org.springframework.cloud.netflix.zuul.filters.discovery.PatternServiceRouteMapper;
import org.springframework.cloud.netflix.zuul.filters.route.SimpleHostRoutingFilter;
import org.springframework.cloud.netflix.zuul.filters.route.ZuulFallbackProvider;
import org.springframework.cloud.netflix.zuul.filters.route.ZuulRoute;
import org.springframework.cloud.netflix.zuul.filters.route.apache.HttpClientRibbonCommandFactory;
import org.springframework.cloud.netflix.zuul.filters.route.apache.HttpClientRibbonCommandFactory.RibbonApacheHttpResponse;
import org.springframework.cloud.netflix.zuul.filters.route.apache.HttpClientRibbonCommandFactory.RibbonHttpResponse;
import org.springframework.cloud.netflix.zuul.filters.route.apache.HttpClientRibbonCommandFactory.SimpleHttpResponse;
import org.springframework.cloud.netflix.zuul.filters.route.apache.HttpClientRibbonCommandFactory.TimedOutRuntimeException;
import org.springframework.cloud.netflix.zuul.filters.route.locator.PatternServiceRouteMapperWrapper;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.OkHttpRibbonHttpResponse;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.SimpleHttpResponse;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.TimedOutException;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.TimedOutRuntimeException;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.TimedOutThrowable;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UnknownHttpStatusCodeException;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommand;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandContext;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandContextKey;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandKey;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandService;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServiceClient;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServiceClientKey;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServiceContext;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServiceContextKey;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServiceKey;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServer;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServerKey;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServerList;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServerListKey;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServerListServer;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp.OkHttpRibbonCommandFactory.UrlRibbonCommandServerListServerKey;
import org.springframework.cloud.netflix.zuul.filters.route.okhttp