Greenwich.SR2版本的Spring Cloud Zuul实例

　　网关作为对外服务，在微服务架构中是一个很重要的组件，主要体现在动态路由和接入鉴权这两个功能上。现在我们通过Spring Cloud Zuul来实现对之前a-feign-client（参见Greenwich.SR2版本的Spring Cloud Feign实例）调用的路由映射，并对外部请求做一个简单的鉴权。三板斧祭出：

　　1、pom里引入spring-cloud-starter-netflix-zuul：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.example</groupId>
  <artifactId>gateway</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>1.8</java.version>
  </properties>

  <dependencies>
    <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-server</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>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>Greenwich.SR2</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、application：

#本机端口
server.port=8765

#服务名
spring.application.name=api-gateway

#注册中心地址
eureka.client.service-url.defaultZone=http://localhost:8888/eureka/

#路由规则
zuul.routes.hello.path=/hello/**

#路由映射
zuul.routes.hello.service-id=a-feign-client

　　3、主类通过@EnableZuulProxy启动网关服务，新增一个过滤器SimpleFilter：

package hello;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.context.annotation.Bean;
import hello.filters.pre.SimpleFilter;

@EnableZuulProxy
@SpringBootApplication
public class GatewayApplication {

  public static void main(String[] args) {
    SpringApplication.run(GatewayApplication.class, args);
  }

  @Bean
  public SimpleFilter simpleFilter() {
    return new SimpleFilter();
  }

}

package hello.filters.pre;

import javax.servlet.http.HttpServletRequest;

import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.ZuulFilter;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SimpleFilter extends ZuulFilter {

    private static Logger log = LoggerFactory.getLogger(SimpleFilter.class);

    @Override
    public String filterType() {
        return "pre";
    }

    @Override
    public int filterOrder() {
        return 1;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @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("accessToken");
        if (accessToken == null) {
            log.warn("access token is empty");
            ctx.setSendZuulResponse(false);
            ctx.setResponseStatusCode(401);
            ctx.setResponseBody("{\"result\":\"accessToken为空!\"}");
            ctx.getResponse().setContentType("text/html;charset=UTF-8");
            return null;
        }
        log.info("access token ok");

        return null;
    }

}

　　OK，我们在浏览器请求http://localhost:8765/hello/consumer/sayHi?name=world看看：

　　加上accessToken参数（参数值随便填一个）再请求一次：

　　我们看到路由和鉴权都实现了。