一、Zuul简介

Zuul是Netflix开源的微服务网关，包含对请求的路由和过滤两个主要功能。

1）路由功能：负责将外部请求转发到具体的微服务实例上，是实现外部访问统一入口的基础。

2）过滤功能：负责对请求的过程进行干预，可以实现请求校验、服务聚合等功能。

二、Zuul代码实现

1）在pom.xml中引入依赖

注意：系统中所有的微服务须连接至Eureka注册中心。Eureka搭建详见另一篇博文：微服务1：搭建微服务注册中心Eureka（命令行简易版，不使用IDE）-CSDN博客

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

完整的pom.xml如下：

<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/maven-v4_0_0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.test</groupId><artifactId>microservice-zuul</artifactId><packaging>jar</packaging><version>1.0-SNAPSHOT</version><name>microservice-zuul</name><url>http://maven.apache.org</url><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.3.0.RELEASE</version><relativePath/> </parent><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>3.8.1</version><scope>test</scope></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></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-eureka-client</artifactId></dependency>   <dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-hystrix</artifactId></dependency> <dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-zuul</artifactId></dependency></dependencies><dependencyManagement><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-dependencies</artifactId><version>Hoxton.SR4</version><type>pom</type><scope>import</scope></dependency>               </dependencies></dependencyManagement><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>

2）配置application.yml

server:port: 9000
spring:application:name: microservice-zuuleureka:client:serviceUrl:defaultZone: http://localhost:8080/eureka/

3）在App.java中添加注解

@EnableDiscoveryClient
@EnableZuulProxy

package com.test;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;@SpringBootApplication
@EnableDiscoveryClient
@EnableZuulProxy
public class App 
{public static void main(String[] args) {SpringApplication.run(App.class, args);}}

三、Zuul测试

在浏览器中输入：

http://localhost:9000/microservice-consumer/users/4

其中microservice-consumer是实际要访问的微服务名称，如果不加Zuul，则该服务的访问URL为：

http://localhost:8010/users/3

使用Zuul网关之后，客户端无需知道每个微服务的端口号，即可通过网关端口号9000来统一访问到系统中所有的微服务。