springcloud学习（六）之zuul

一、介绍

Spring Cloud Zuul路由是微服务架构的不可或缺的一部分，提供动态路由，监控，弹性，安全等的边缘服务。Zuul是Netflix出品的一个基于JVM路由和服务端的负载均衡器。

二、开发

1、新建项目hjduan.spring.cloud.zuul pom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/xsd/maven-4.0.0.xsd">    <modelVersion>4.0.0</modelVersion>    <parent>        <groupId>com.hjduan.spring.cloud</groupId>        <artifactId>hjduan.spring.cloud</artifactId>        <version>0.0.1-SNAPSHOT</version>    </parent>    <artifactId>hjduan.spring.cloud.zuul</artifactId>    <dependencies>        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-eureka</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-zuul</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>    </dependencies>    <build>        <plugins>            <plugin>                <groupId>org.springframework.boot</groupId>                <artifactId>spring-boot-maven-plugin</artifactId>            </plugin>        </plugins>    </build></project>

2、application.yml配置

server:  port: 8767eureka:  client:    serviceUrl:      defaultZone: http://admin:admin@localhost:8761/eureka/  instance:    prefer-ip-address: true    instance-id: ${spring.application.name}:${spring.application.instance_id:${server.port}}spring:  application:    name: hjduan-spring-cloud-zuul#zuul 充当路由zuul:  routes:    api-a:      path: /api-a/**      serviceId: HJDUAN-SPRING-CLOUD-RIBBON    api-b:      path: /api-b/**      serviceId: HJDUAN-SPRING-CLOUD-FEIGN

3、编写一个过滤器MyFilter.java

package com.hjduan.spring.cloud.zuul.filter;import javax.servlet.http.HttpServletRequest;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Component;import com.netflix.zuul.ZuulFilter;import com.netflix.zuul.context.RequestContext;/** * 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。 *  * 作者： 段浩杰 2017年7月25日 */@Componentpublic class MyFilter extends ZuulFilter {    private static Logger log = LoggerFactory.getLogger(MyFilter.class);    @Override    public String filterType() {        return "pre";    }    @Override    public int filterOrder() {        return 0;    }    @Override    public boolean shouldFilter() {        return true;    }    @Override    public Object run() {        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;    }}

4、编写启动类

package com.hjduan.spring.cloud.zuul;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;@EnableZuulProxy@EnableEurekaClient@SpringBootApplicationpublic class ServiceZuulApplication {    public static void main(String[] args) {        SpringApplication.run(ServiceZuulApplication.class, args);    }}

5、启动hjduan.spring.cloud.eureka，hjduan.spring.cloud.consumer，修改端口再次启动hjduan.spring.cloud.consumer，hjduan.spring.cloud.feign，hjduan.spring.cloud.hystrix，hjduan.spring.cloud.ribbon，hjduan.spring.cloud.zuul，然后运行http://localhost:8767/api-a/hi/123和http://localhost:8767/api-b/hi/123观察结果