spring-cloud（六）路由器和过滤器[Zuul]

路由在微服务体系结构的一个组成部分。

例如，/可以映射到您的Web应用程序，/api/users映射到用户服务，并将/api/shop映射到商店服务。

Zuul是Netflix的基于JVM的路由器和服务器端负载均衡器。

本案例示例代码在 spring-cloud（三）声明性REST客户端[Feign] 及 spring-cloud（五）客户端负载平衡器[Ribbon] 基础上进行改造。

1.创建一个maven工程，tm-service-zuul

2.在pom文件中引入zuul的依赖支持

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

3.在application.yml文件中增加zuul的路由规则

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
server:
  port: 8767
spring:
  application:
    name: service-zuul
zuul:
  routes:
    api-ribbon:
      path: /api-r/**
      serviceId: service-ribbon
    api-feign:
      path: /api-f/**
      serviceId: service-feign

4.在主启动类上增加注解 @EnableZuulProxy

@EnableZuulProxy
@SpringBootApplication
@EnableDiscoveryClient
public class ServiceZuulApplication {
    public static void main(String[] args) {
        SpringApplication.run(ServiceZuulApplication.class, args);
    }
}

5.分别启动 tm-eureka-server，tm-service，tm-service-feign，tm-service-ribbon，tm-service-zuul

6.浏览器访问
http://192.168.2.14:8767/api-f/hello

http://192.168.2.14:8767/api-r/hello

出现如上图所示响应，说明路由规则生效了。

7.再增加filter类，创建TmFilter

package cn.majingjing.tm.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;
@Component
public class TmFilter extends ZuulFilter {
    private static Logger log = LoggerFactory.getLogger(TmFilter.class);
    @Override
    public Object run() {
        RequestContext ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();
        log.info("{} , {}", request.getMethod(), request.getRequestURL().toString());
        Object token = request.getParameter("token");
        if (token == null || !"zuul".equals(token)) {
            ctx.setSendZuulResponse(false);
            ctx.setResponseStatusCode(401);
            try {
                ctx.getResponse().getWriter().write("token is invalid");
            } catch (Exception e) {
            }
            return null;
        }
        return null;
    }
    @Override
    public boolean shouldFilter() {
        return true;
    }
    @Override
    public int filterOrder() {
        return 0;
    }
    @Override
    public String filterType() {
        return "pre";
    }
}

8.再次启动服务，并重复步骤6，发现请求被禁止。token无效

可以基于zuul的过滤器也生效了。

以上就是zuul的简单使用示例。