1、Zuul簡介
Zuul作爲微服務系統的網關組件，用於構建邊界服務（Edge Service），致力於動態路由、過濾、監控、彈性伸縮和安全。其在微服務架構中有着重要的作用，主要體現在以下六個方面：
- Zull、Ribbon以及Eureka相結合可以實現智能路由和負載均衡的功能，Zull可以按照某種策略將請求分發到不同的實例上
- 網關作爲邊界服務，將內部服務的API接口進行聚合並統一對外暴露接口。保護內部服務的API接口，防止內部服務被外界調用泄露敏感信息；
- 網關可以對用戶的身份權限進行認證，防止非法請求API接口；
- 網關可以實現監控功能，實時日誌輸出，對請求進行記錄；
- 網關可以用來實現流量監控，在高流量的情況下，對服務進行降級；
- API接口從內部服務分離出來，便於測試
2、創建一個Zuul工程作爲網關
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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>service-zuul</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>service-zuul</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-zuul</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</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>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
</project>
application.yml，這裏配置了兩種路由，以ribbon開頭的請求都會轉發到實例service-ribbon上，以feign開頭的請求會轉發到實例service-feign上
server:
port: 8005
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8000/eureka/
spring:
application:
name: service-zuul
zuul:
routes:
api-a:
path: /ribbon/**
serviceId: service-ribbon
api-b:
path: /feign/**
serviceId: service-feign
啓動類上添加@EnableZuulProxy開啓zuul服務
@SpringBootApplication
@EnableEurekaClient
@EnableZuulProxy
public class ServiceZuulApplication {
public static void main(String[] args) {
SpringApplication.run(ServiceZuulApplication.class, args);
}
}
3、測試
訪問：http://localhost:8005/ribbon/test/hello，可以看到8001和8002在輪詢打印，說明路由已經起了作用
Hello world,this is eureka-client1--8001
Hello world,this is eureka-client1--8002
訪問：http://localhost:8005/feign/test/hello，同樣8001和8002在輪詢打印
Hello world,this is eureka-client1--8001
Hello world,this is eureka-client1--8002
4、服務過濾
這裏可以過濾用戶的請求，並可以對用戶的請求做一些校驗操作，比如Token校驗
/**
* @author XuJD
* @create 2019-11-28 15:15
**/
@Component
public class RouteFilter 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();
Object accessToken = request.getParameter("token");
if(accessToken == null) {
ctx.setSendZuulResponse(false);
ctx.setResponseStatusCode(401);
try {
ctx.getResponse().getWriter().write("token is empty");
}catch (Exception e){}
return null;
}
return null;
}
filterType：過濾類型，在zuul種提供了4種不同生命週期的過濾類型
pre：路由之前
routing：路由之時
post： 路由之後
error：發送錯誤調用
filterOrder：過濾順序
shouldFilter：是否需要過濾
run：過濾器的具體邏輯
這時候再訪問：http://localhost:8005/feign/test/hello
token is empty
帶上token則可以正常訪問
http://localhost:8005/ribbon/test/hello?token=123
Hello world,this is eureka-client1--8001
Hello world,this is eureka-client1--8002
