The use of springCloud 05-----routing gateway (zuul)

The main function of zuul is routing forwarding and filtering. For example, all requests from /api-a/* are forwarded to server a, and all requests from /api-b/* are forwarded to server b. By default, zuul is implemented in combination with ribbon. Load balancing function.

1 zuul's routing forwarding

　　1.1 Create a springboot project and introduce related dependencies

<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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.beifeng.hadoop</groupId>
    <artifactId>beifeng-spring-cloud-zuul</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>beifeng-spring-cloud-zuul</name>
    <url>http://maven.apache.org</url>
    
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath />
    </parent>

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

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- 声明为web项目 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- 配置eureka -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        
        <!-- 配置zuul -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zuul</artifactId>
        </dependency>
    </dependencies>
    
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Dalston.RC1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
</project>

　　1.2 Configure the routing forwarding policy in the configuration file

eureka:
 client:
  serviceUrl:
   defaultZone: http://localhost:8761/eureka/ #Register server address
server:
  port: 8766
spring:
  application:
    name: cloud-zuul
zuul:
 routes:
  api-a:
   path: /api-a/** #All requests starting with /api-a are forwarded to the cloud-consumer-ribbon server
   serviceId: cloud-consumer-ribbon
  api-b:
   path: /api-b/** #All requests starting with /api-b are forwarded to the cloud-consumer-feign server
   serviceId: cloud-consumer-feign

　　1.3 Declare enabling zuul in the startup class

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

　　1.4 Start to view the results

　　　　Start the eureka-server, eureka-client, cloud-consumer-ribbon, cloud-consumer-feign, cloud-zuul projects in sequence

　　　　

　　　  

 2 Route filtering

　　2.1 Create a custom route filter, specify which requests to filter and how to filter

@Component
public class MyZuulFilter extends ZuulFilter {
    
    Logger logger=LoggerFactory.getLogger(MyZuulFilter.class);

    // The specific logic of the filter 
    public Object run() {
        RequestContext context=RequestContext.getCurrentContext();
        HttpServletRequest request=context.getRequest();
        logger.info("url:"+request.getRequestURL().toString());
        Object token=request.getParameter("token");
        if (token==null||StringUtils.isEmpty(token.toString())) {
            logger.info("token is empty");
            context.setSendZuulResponse ( false );
            context.setResponseStatusCode(401);
            try {
                context.getResponse().getWriter().write("token is empty");
            } catch (IOException e) {
                e.printStackTrace ();
            }
            return null;
        }
        logger.info("ok");
        return null;
    }

    // Whether to filter, you can write logical judgment 
    public  boolean shouldFilter() {
        RequestContext context=RequestContext.getCurrentContext();
        HttpServletRequest request=context.getRequest();
        String url = request.getRequestURL().toString();
         return url.contains("/api-a/"); // Only verify the request of api-a 
    }

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

    // Return the type of filter, pre: before routing, routing: during routing, post: after routing, error: call 
    @Override
     when an error occurs public String filterType() {
         return "pre" ;
    }
}

　　2.2 Start to view the effect