Spring cloud学习笔记8-路由网关Zuul

1. 概述

路由在微服务架构的一个组成部分。 例如，/可以映射到您的Web应用程序，/ api / users映射到用户服务，并且/ 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。
其功能包括
1） 验证
2） 见解
3） 压力测试
4） 金丝雀测试
5） 动态路由
6） 服务迁移
7） 减载
8） 安全
9） 静态响应处理
10） 主动/主动流量管理
Zuul的规则引擎允许规则和过滤器基本上用任何JVM语言编写，内置支持Java和Groovy。

2. 路由

2.1 新建工程

新建一个maven的module工程，名称为service-feign，父亲pom为springcloud。需要引入eureka-client、zuul、starter-web的jar包，Pom文件如下：

2.2 Pom引入jar

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<artifactId>spring-cloud</artifactId>
		<groupId>com.lin</groupId>
		<version>0.0.1-SNAPSHOT</version>
	</parent>

	<groupId>com.lin</groupId>
	<artifactId>spring-zuul</artifactId>
	<version>0.0.1-SNAPSHOT</version>

	<name>spring-zuul</name>
	<!-- FIXME change it to the project's website -->
	<url>http://www.example.com</url>


	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.11</version>
			<scope>test</scope>
		</dependency>
		<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-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-zuul</artifactId>
		</dependency>
	</dependencies>

	<build>
		<pluginManagement><!-- lock down plugins versions to avoid using Maven 
				defaults (may be moved to parent pom) -->
			<plugins>
				<plugin>
					<artifactId>maven-clean-plugin</artifactId>
					<version>3.0.0</version>
				</plugin>
				<!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
				<plugin>
					<artifactId>maven-resources-plugin</artifactId>
					<version>3.0.2</version>
				</plugin>
				<plugin>
					<artifactId>maven-compiler-plugin</artifactId>
					<version>3.7.0</version>
				</plugin>
				<plugin>
					<artifactId>maven-surefire-plugin</artifactId>
					<version>2.20.1</version>
				</plugin>
				<plugin>
					<artifactId>maven-jar-plugin</artifactId>
					<version>3.0.2</version>
				</plugin>
				<plugin>
					<artifactId>maven-install-plugin</artifactId>
					<version>2.5.2</version>
				</plugin>
				<plugin>
					<artifactId>maven-deploy-plugin</artifactId>
					<version>2.8.2</version>
				</plugin>
				<plugin>
					<groupId>org.springframework.boot</groupId>
					<artifactId>spring-boot-maven-plugin</artifactId>
				</plugin>
			</plugins>
		</pluginManagement>
	</build>
</project>

2.3 启动类

编写一个启动类ServiceZuulApplication.java，引入@EnableZuulProxy注解。代码如下：

package org.spring.zuul;
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;
@SpringBootApplication
@EnableZuulProxy
@EnableEurekaClient
public class ServiceZuulApplication {
	public static void main(String[] args) {
        SpringApplication.run( ServiceZuulApplication.class, args );
    }
	
}

2.4 配置文件application

建立一个resources文件夹，在其下面新建一个application.yml文件，使用zuul做一个路由，配置如下:

server:
  port: 8769

spring:
  application:
    name: service-zuul

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

zuul:
  routes:
    api-a:
      path: /api-a/**
      serviceId: service-ribbon
    api-b:
      path: /api-b/**
      serviceId: service-feign

3. 过滤器

3.1 建立过滤器

建立过滤器MyFilter.java，继承ZuulFilter，实现方法。

package org.spring.zuul;
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;
import com.netflix.zuul.exception.ZuulException;
@Component
public class MyFilter extends ZuulFilter {
	private static Logger log = LoggerFactory.getLogger(MyFilter.class);
	@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;
        }
        log.info("ok");
        return null;
	}
	@Override
	public boolean shouldFilter() {
		return true;
	}
	@Override
	public int filterOrder() {
		return 0;
	}
	@Override
	public String filterType() {
		return "pre";
	}
}

3.2 配置过滤器

在启动类ServiceZuulApplication.java中把过滤器配置进去即可。代码如下：

package org.spring.zuul;
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;
import org.springframework.context.annotation.Bean;
@SpringBootApplication
@EnableZuulProxy
@EnableEurekaClient
public class ServiceZuulApplication {
	public static void main(String[] args) {
        SpringApplication.run( ServiceZuulApplication.class, args );
    }
		@Bean
	public MyFilter myFilter(){
		return new MyFilter();
	}
}

本文参考文献：https://blog.youkuaiyun.com/forezp/article/details/70148833/