SpringCloud微服务架构搭建（四）：动态路由

Zuul的主要功能是路由和过滤器。路由功能是微服务的一部分，zuul实现了负载均衡。

1.1
新建模块zuul
pom.xml

<?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">    <parent>        <artifactId>spring-cloud</artifactId>        <groupId>com.feng</groupId>        <version>0.0.1</version>    </parent>    <modelVersion>4.0.0</modelVersion>    <artifactId>zuul</artifactId>    <dependencies>        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-zuul</artifactId>        </dependency>    </dependencies></project>

1.2
application.yml:

spring:  application:    name: zuulserver:  port: 8020eureka:  client:    service-url:      defaultZone: http://localhost:8010/eureka/zuul:  routes:    api-a:      path: /service-a/**      serviceId: service-a    api-b:      path: /service-b/**      serviceId: service-b  sensitive-headers:  #设置忽略的头信息，设置为空能解决会话保持问题  add-host-header: true #设为true才能保持Host头信息处理正确

上面配置说明把/service-a/开头的所有请求都转发给service-a服务执行，把/service-b/开头的所有请求都转发给service-b服务执行

1.3
ZuulApplication，使用EnableZuulProxy注解开启zuul功能，并且注册了一个zuul的过滤器

@SpringCloudApplication //这个注解整合了@SpringBootApplication、@EnableDiscoveryClient、@EnableCircuitBreake@EnableZuulProxypublic class ZuulApplication {    public static void main(String[] args) {        SpringApplication.run(ZuulApplication.class, args);    }    @Bean    public MyZuulFilter getZuulFilter(){        return new MyZuulFilter();    }}

MyZuulFilter，过滤器加了个判断id是否为空，空则返回401错误码

public class MyZuulFilter extends ZuulFilter {    private static Logger log = LoggerFactory.getLogger(MyZuulFilter.class);    /**     * 返回过滤器类型     * @return     *  pre：可以在请求被路由之前调用     *  routing：在路由请求时候被调用     *  post：在routing和error过滤器之后被调用     *  error：处理请求时发生错误时被调用     */    @Override    public String filterType() {        return "pre";    }    /**     * 通过int值来定义过滤器的执行顺序     */    @Override    public int filterOrder() {        return 0;    }    /**     * 判断过滤器是否执行     */    @Override    public boolean shouldFilter() {        return true;    }    /**     * 过滤器的具体逻辑     *  ctx.setSendZuulResponse(false)令zuul不允许请求，     *  ctx.setResponseStatusCode(401)设置了其返回的错误码     *  ctx.setResponseBody(body)编辑返回body内容     * @return     */    @Override    public Object run() {        RequestContext ctx = RequestContext.getCurrentContext();        HttpServletRequest request = ctx.getRequest();        log.info(String.format("%s request to %s", request.getMethod(), request.getRequestURL().toString()));        Object accessToken = request.getParameter("id");        if(accessToken == null) {            log.warn("id is null");            ctx.setSendZuulResponse(false);            ctx.setResponseStatusCode(401);            return null;        }        log.info("pass!");        return null;    }}

1.4

把之前负载的service-b的spring.application.name改为service-b, 运行项目，分别打开http://localhost:8020/service-a/hi?id=zuul和http://localhost:8020/service-b/hi?id=zuul