SpringCloud 2.x学习笔记：4、Zuul（Greenwich版本）

r囧r小猫 2022-04-25 10:34 209阅读 0赞

### 1、Zuul简介 ###

zuul 是netflix开源的一个API Gateway 服务器, 本质上是一个web servlet应用。

请参考官方文档：  
[https://springcloud.cc/spring-cloud-dalston.html\#\_router\_and\_filter\_zuul][https_springcloud.cc_spring-cloud-dalston.html_router_and_filter_zuul]

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／api/user转发到到user服务，/api/shop转发到到shop服务。zuul默认和Ribbon结合实现了负载均衡的功能。

### 2、新建模块 ###

#### 2.1 pom文件 ####

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <groupId>com.cntaiping.tpa</groupId>
        <artifactId>zuul</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
        <name>zuul</name>
        <description>Demo project for Spring Boot</description>
    
        <parent>
            <groupId>com.cntaiping.tpa</groupId>
            <artifactId>cloud</artifactId>
            <version>1.0-SNAPSHOT</version>
        </parent>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
            </dependency>
        </dependencies>
    </project>

#### 2.2 application.properties ####

eureka.client.serviceUrl.defaultZone=http://localhost:8800/eureka/
    server.port=8400
    spring.application.name=service-zuul
    #表示只要访问以/api-a/开头的多层目录都可以路由到 id为compute-service的服务上
    zuul.routes.consumer-feign=/api-a/**
    zuul.routes.consumer-hystrix=/api-b/**

服务消费者也可以作为服务提供者。  
以/api-a/ 开头的请求都转发给consumer-feign服务；以/api-b/开头的请求都转发给consumer-hystrix服务；

#### 2.3 Application类 ####

package com.cntaiping.tpa.zuul;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.SpringCloudApplication;
    import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
    
    /**
     * @SpringCloudApplication注解
     * 整合了@SpringBootApplication、@EnableEurekaClient、@EnableCircuitBreaker
     * 主要目的还是简化配置
     */
    @EnableZuulProxy
    @SpringCloudApplication
    public class ZuulApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(ZuulApplication.class, args);
        }
    
    }

#### 2.4 运行效果 ####

从执行结果可以说明zuul起到了路由的作用  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 1]

### 3、过滤器 ###

可以通过zuul提供的过滤器，进行一些请求过滤，比如安全验证。  
停止模块，增加过滤器类如下。

package com.cntaiping.tpa.zuul.filter;
    
    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;
    
    @Component
    public class TokenFilter extends ZuulFilter {
    
        private static Logger log = LoggerFactory.getLogger(TokenFilter.class);
    
       /**
        返回一个字符串代表过滤器的类型，
        pre：路由之前
        routing：路由之时
        post： 路由之后
        error：发送错误调用
       */
        @Override
        public String filterType() {
            return "pre";
        }
    
        /**
          过滤的顺序
       */
        @Override
        public int filterOrder() {
            return 0;
        }
    
        /**
          这里可以写逻辑判断，是否要过滤，本文true,永远过滤。
        */
        @Override
        public boolean shouldFilter() {
            return true;
        }
    
        /**
          过滤器的具体逻辑。
       */
        @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;
        }
    }

重新运行模块  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 2]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 3]

[http://localhost:8400/api-a/hello?name=chengyq&token=111][http_localhost_8400_api-a_hello_name_chengyq_token_111]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 4]

[https_springcloud.cc_spring-cloud-dalston.html_router_and_filter_zuul]: https://springcloud.cc/spring-cloud-dalston.html#_router_and_filter_zuul
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70]: /images/20220125/718818888d654238a19a0434b6816c86.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 1]: /images/20220125/13bf3770261743808e61cf2acaa19224.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 2]: /images/20220125/56da99eeb1354b6a90e5ca7726252c7e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 3]: /images/20220125/13243738249e452eb863ea7eb22eb833.png
[http_localhost_8400_api-a_hello_name_chengyq_token_111]: http://localhost:8400/api-a/hello?name=chengyq&token=111
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 4]: /images/20220125/22afd452265b4dc6916fe43c9463d864.png