原创

第五篇 : 路由网关(Zuul)


一、Zuul简介

Zuul的主要功能是路由转发和过滤器。路由功能是微服务的一部分,比如/api/user转发到到user服务,/api/shop转发到到shop服务。zuul默认和Ribbon结合实现了负载均衡的功能。

二、创建项目

为了备份源码,复制项目使用。

三、创建 service-zuul 工程

1. 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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.gf</groupId>
	<artifactId>service-zuul</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>service-zuul</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>com.gf</groupId>
		<artifactId>chapter05</artifactId>
		<version>0.0.1-SNAPSHOT</version>
	</parent>

	<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-server</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-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>


</project>

2. 主程序启动类 ServiceZuulApplication

在其入口applicaton类加上注解@EnableZuulProxy,开启zuul的功能:

package com.gf;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@EnableZuulProxy
public class ServiceZuulApplication {

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

3. application.yml

加上配置文件application.yml加上以下的配置代码:

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
server:
  port: 8769
spring:
  application:
    name: service-zuul
zuul:
  routes:
    api-a:
      path: /api-a/**
      serviceId: service-ribbon
    api-b:
      path: /api-b/**
      serviceId: service-feign

首先指定服务注册中心的地址为http://localhost:8761/eureka/,服务的端口为8769,服务名为service-zuul;以/api-a/ 开头的请求都转发给service-ribbon服务;以/api-b/开头的请求都转发给service-feign服务;

依次运行这五个工程;打开浏览器访问:http://localhost:8769/api-a/hi ;浏览器显示:

hello , port is 8762

打开浏览器访问:http://localhost:8769/api-b/hi ;浏览器显示:

hello , port is 8762

这说明zuul起到了路由的作用。

四、服务过滤

zuul不仅只是路由,并且还能过滤,做一些安全验证。继续改造工程;

package com.gf.config;


import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

@Component
public class MyFilter extends ZuulFilter{

    private static Logger logger = LoggerFactory.getLogger( MyFilter.class);

    /**
     * pre : 路由访问之时
     */
    @Override
    public String filterType() {
        return "pre";
    }

    /**
     * filterOrder : 过滤的顺序
     */
    @Override
    public int filterOrder() {
        return 0;
    }

    /**
     * shouldFilter : 这里可以写逻辑判断,是否过滤
     */
    @Override
    public boolean shouldFilter() {
        return true;
    }

    /**
     * run : 过滤的具体逻辑判断,可以很复杂,包括sql,nosql去判断请求有没有权限访问
     */
    @Override
    public Object run() throws ZuulException {
        RequestContext ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();
        logger.info( String.format("%s >>> %s" , request.getMethod() , request.getRequestURL()) );
        Object accessToken = request.getParameter( "token" );
        if (null == accessToken) {
            logger.warn( "token is empty" );
            ctx.setSendZuulResponse( false );
            ctx.setResponseStatusCode( 401 );
            try {
                ctx.getResponse().getWriter().write( "token is empty" );
            } catch (IOException e) {
                e.printStackTrace();
            }

            return null;

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

}

filterType:返回一个字符串代表过滤器的类型,在zuul中定义了四种不同生命周期的过滤器类型,具体如下:

  • pre:路由之前
  • routing:路由之时
  • post: 路由之后
  • error:发送错误调用
  • filterOrder:过滤的顺序
  • shouldFilter:这里可以写逻辑判断,是否要过滤,本文true,永远过滤。
  • run:过滤器的具体逻辑。可用很复杂,包括查sql,nosql去判断该请求到底有没有权限访问。

这时访问:http://localhost:8769/api-a/hi ;网页显示:

token is empty

访问 http://localhost:8769/api-a/hi?token=22 ;网页显示:

hello , port is 8762

源码下载:https://github.com/gf-huanchupk/SpringCloudLearning

springcloud
  • 作者:程序员果果
  • 发表时间:2018-09-22 20:37
  • 版权声明:自由转载-非商用-非衍生-保持署名 (创意共享4.0许可证)
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