Spring Cloud基础教程（七）：路由网关使用（Zuul）

水深无声 2022-05-24 11:10 192阅读 0赞

# 一、概述 #

Zuul的主要功能是路由转发和过滤器。路由功能是微服务的一部分，比如/client-a/转发到到a服务，/client-b/转发到到b服务。zuul默认和Ribbon结合实现了负载均衡的功能。

# 二、准备 #

将[服务注册与发现][Link 1]这篇博客中的Eureka-Client-A工程，复制一份，名字修改为Service-Zuul。

# 三、工程修改 #

Gradle依赖修改为

dependencies {
    	compile('org.springframework.cloud:spring-cloud-starter-netflix-eureka-client')
    	compile('org.springframework.cloud:spring-cloud-starter-zuul:1.4.4.RELEASE')
    	compile('org.springframework.boot:spring-boot-starter-web')
    	testCompile('org.springframework.boot:spring-boot-starter-test')
    }

在启动类上添加@EnableZuulProxy注解，开启路由功能。

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
    
    @SpringBootApplication
    @EnableEurekaClient
    @EnableZuulProxy
    public class EurekaZuulApplication
    {
    
    	public static void main(String[] args) {
    		SpringApplication.run(EurekaZuulApplication.class, args);
    	}
    }

修改application.properties配置文件，将/client-a/开头的请求路由到eureka-client-a服务器

spring.application.name=service-zuul
    server.port=10010
    eureka.client.serviceUrl.defaultZone=http://localhost:10001/eureka/
    
    zuul.routes.api-a.path: /client-a/**
    zuul.routes.api-a.serviceId: eureka-client-a

# 四、测试 #

启动之前的Eureka-Server、Eureka-Client-A和当前的Service-Zuul工程，访问[http://127.0.0.1:10001/][http_127.0.0.1_10001]

![20180525210822244][]

发现都已经注册到了注册中心，访问[http://127.0.0.1:10010/client-a/client][http_127.0.0.1_10010_client-a_client]，会发现路由到了Eureka-Client-A

![20180525210920922][]

# 五、服务过滤 #

Zuul不仅有路由的功能，还有服务过滤的功能，做一些拦截验证。

新建MyFilter类

import com.netflix.zuul.ZuulFilter;
    import com.netflix.zuul.context.RequestContext;
    import com.netflix.zuul.exception.ZuulException;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    
    import javax.servlet.http.HttpServletRequest;
    
    /**
     * Created by wzj on 2018/5/24.
     */
    @Component
    public class MyFilter extends ZuulFilter
    {
        private static Logger log = LoggerFactory.getLogger(MyFilter.class);
    
        /**
         * to classify a filter by type. Standard types in Zuul are "pre" for pre-routing filtering,
         * "route" for routing to an origin, "post" for post-routing filters, "error" for error handling.
         * We also support a "static" type for static responses see  StaticResponseFilter.
         * Any filterType made be created or added and run by calling FilterProcessor.runFilters(type)
         *
         * @return A String representing that type
         */
        @Override
        public String filterType()
        {
            return "pre";
        }
    
        /**
         * filterOrder() must also be defined for a filter. Filters may have the same  filterOrder if precedence is not
         * important for a filter. filterOrders do not need to be sequential.
         *
         * @return the int order of a filter
         */
        @Override
        public int filterOrder()
        {
            return 0;
        }
    
        /**
         * a "true" return from this method means that the run() method should be invoked
         *
         * @return true if the run() method should be invoked. false will not invoke the run() method
         */
        @Override
        public boolean shouldFilter()
        {
            return true;
        }
    
        /**
         * if shouldFilter() is true, this method will be invoked. this method is the core method of a ZuulFilter
         *
         * @return Some arbitrary artifact may be returned. Current implementation ignores it.
         * @throws ZuulException if an error occurs during execution.
         */
        @Override
        public Object run() throws ZuulException
        {
            RequestContext ctx = RequestContext.getCurrentContext();
            HttpServletRequest request = ctx.getRequest();
            log.info(String.format("%s >>> %s", request.getMethod(), request.getRequestURL().toString()));
            Object accessToken = request.getParameter("token");
            if (accessToken == null)
            {
                log.warn("token is empty");
                ctx.setSendZuulResponse(false);
                ctx.setResponseStatusCode(401);
                try
                {
                    ctx.getResponse().getWriter().write("token is empty");
                }
                catch (Exception e)
                {
                }
    
                return null;
            }
            log.info("ok");
            return null;
        }
    }

filterType：返回一个字符串代表过滤器的类型，在zuul中定义了四种不同生命周期的过滤器类型，具体如下：

*  pre：路由之前
 *  routing：路由之时
 *  post： 路由之后
 *  error：发送错误调用
 *  filterOrder：过滤的顺序
 *  shouldFilter：这里可以写逻辑判断，是否要过滤，本文true,永远过滤。
 *  run：过滤器的具体逻辑。可用很复杂，包括查sql，nosql去判断该请求到底有没有权限访问。

服务重启，再次访问[http://127.0.0.1:10010/client-a/client][http_127.0.0.1_10010_client-a_client]，界面显示如下

![20180525211235912][]

再次输入[http://127.0.0.1:10010/client-a/client?token=1001][http_127.0.0.1_10010_client-a_client_token_1001]

![20180525212936314][]

[Link 1]: https://blog.csdn.net/u010889616/article/details/80315205
[http_127.0.0.1_10001]: http://127.0.0.1:10001/
[20180525210822244]: /images/20220524/3f8b3fd85ccc4517aade0660e42f3600.png
[http_127.0.0.1_10010_client-a_client]: http://127.0.0.1:10010/client-a/client
[20180525210920922]: /images/20220524/ee210e8a031d46dda33a13c3db3897a9.png
[20180525211235912]: /images/20220524/3d06620a7732488eb1217e1f89ce0c94.png
[http_127.0.0.1_10010_client-a_client_token_1001]: http://127.0.0.1:10010/client-a/client?token=1001
[20180525212936314]: /images/20220524/313aaf9dc1754c4fb362ec8b7310d0f8.png