【前面的話】書接上文，前面已經講過了SpringCloud的注冊中心Eureka、Ribbon和Feign等等，如果有不清楚的也可以去看看我的微服務系列文章，這篇文章我要說的是微服務中的網關，

壹、Zuul的簡介

Zuul的主要功能是路由轉發和過濾器，路由功能是微服務的一部分，比如／api/user轉發到到user服務，/api/shop轉發到到shop服務，zuul默認和Ribbon結合實作了負載均衡的功能，

zuul有以下功能：

Authentication
Insights
Stress Testing
Canary Testing
Dynamic Routing
Service Migration
Load Shedding
Security
Static Response handling
Active/Active traffic management

貳、準備作業

新建一個feign子工程lovin-cloud-zuul，用于后面的操作，下面是主要的pom依賴:

<parent>
        <artifactId>lovincloud</artifactId>
        <groupId>com.eelve.lovincloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>lovin-cloud-zuul</artifactId>
    <packaging>jar</packaging>
    <name>lovincloudzuul</name>
    <version>0.0.1</version>
    <description>zuul</description>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zuul</artifactId>
            <version>1.4.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

這里為了安全，我這里還是添加spring-boot-starter-security，同時配置路由規則發送/api-ribbon/打頭開始的服務轉發到lovinribbonclient而發送/api-feign/打頭的服務轉發到lovinfeignclient，可以看出這里是配置相應的路由規則，

server:
  port: 8882   # 服務埠號
spring:
  application:
    name: lovincloudzuul     # 服務名稱
  security:
    basic:
      enabled: true
    user:
      name: lovin
      password: ${REGISTRY_SERVER_PASSWORD:lovin}
zuul:
  routes:
    api-ribbon:
      path: /api-ribbon/**
      serviceId: lovinribbonclient
    api-feign:
      path: /api-feign/**
      serviceId: lovinfeignclient
eureka:
  client:
    serviceUrl:
      defaultZone: http://lovin:lovin@localhost:8881/eureka/   # 注冊到的eureka服務地址
  instance:
    leaseRenewalIntervalInSeconds: 10
    health-check-url-path: /actuator/health
    metadata-map:
      user.name: lovin
      user.password: lovin

配置spring-boot-starter-security，這里為了方便我這里放開所有請求

package com.eelve.lovin.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

/**
 * @ClassName WebSecurityConfig
 * @Description TDO
 * @Author zhao.zhilue
 * @Date 2019/8/18 12:17
 * @Version 1.0
 **/
@Configuration
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests().anyRequest().permitAll()
                .and().csrf().disable();
    }
}

在主類上添加@EnableZuulProxy ，當然也需要注冊到注冊中心：

package com.eelve.lovin;

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;

/**
 * @ClassName LovinEurekaClientApplication
 * @Description TDO
 * @Author zhao.zhilue
 * @Date 2019/8/15 16:37
 * @Version 1.0
 **/
@EnableZuulProxy
@EnableEurekaClient
@SpringBootApplication
public class LovinCloudZuulApplication {
    public static void main(String[] args) {
        SpringApplication.run(LovinCloudZuulApplication.class,args);
    }
}

這里為了方便測驗，這里配置相應的過濾規則：

package com.eelve.lovin.filter;

import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;

/**
 * @ClassName MyFilter
 * @Description TDO
 * @Author zhao.zhilue
 * @Date 2019/8/18 12:44
 * @Version 1.0
 **/
@Component
@RefreshScope // 使用該注解的類，會在接到SpringCloud配置中心配置重繪的時候，自動將新的配置更新到該類對應的欄位中，
@Slf4j
public class MyFilter extends ZuulFilter {

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

    @Override
    public int filterOrder() {
        return 0;
    }

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

    @Override
    public Object run() throws ZuulException {
        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;
        }else if(!accessToken.equals("lovin")){
            log.warn("token is not correct");
            ctx.setSendZuulResponse(false);
            ctx.setResponseStatusCode(403);
            try {
                ctx.getResponse().getWriter().write("token is not correct");
            }catch (Exception e){}

            return null;
        }
        log.info("ok");
        return null;
    }
}

    filterType：回傳一個字串代表過濾器的型別，在zuul中定義了四種不同生命周期的過濾器型別，具體如下：
        pre：路由之前
        routing：路由之時
        post： 路由之后
        error：發送錯誤呼叫
    filterOrder：過濾的順序
    shouldFilter：這里可以寫邏輯判斷，是否要過濾，本文true,永遠過濾，
    run：過濾器的具體邏輯，可用很復雜，包括查sql，nosql去判斷該請求到底有沒有權限訪問，

叁、啟動測驗

依次啟動eureka的服務端和兩個客戶端和lovin-feign-client、lovin-ribbon-client，以及新建的lovin-cloud-zuul
然后訪問http://localhost:8882/api-feign/getHello和http://localhost:8882/api-ribbon/hello，然后我們可以帶上token訪問來驗證過濾器