第四篇：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／user/**转发到到user服务，/api/**转发到到api服务。zuul默认和Ribbon结合实现了负载均衡的功能。

二  Zuul的路由功能

创建一个Module 叫zuul

创建完成之后的pom如下：

<?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.hmzj</groupId>
    <artifactId>zuul</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

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

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <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-starter-test</artifactId>
            <scope>test</scope>
        </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>


</project>

创建application.yml

server:
  port: 8062
spring:
  application:
    name: zuul
eureka:
  instance:
    prefer-ip-address: true
    instance-id: ${spring.cloud.client.ip-address}:${spring.application.name}:${server.port}
  client:
    serviceUrl:
      defaultZone: http://**:**@192.168.31.54:8060/eureka/
zuul:
  routes:
    user: #localhost:8062/user/**中的user
      path: /user/** #转发user/下的所有请求
      serviceId: callcenter-user #服务名称
    freeswitch:
      path: /freeswitch/**
      serviceId: callcenter-freeswitch
    api:
      path: /api/**
      serviceId: callcenter-api

 其中路由部分就是routes下面的部分 

启动服务

 

访问http://localhost:8062/user/test/sayHello/pyq 8062是zuul的端口

 二  Zuul的过滤器功能

在根目录下新建MyFilter.java

package com.hmzj.zuul;

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

import javax.servlet.http.HttpServletRequest;

@Component
public class MyFilter extends ZuulFilter {

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

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

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

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

    @Override
    public Object run() {
        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 false;
        }
        log.info("ok");
        return true;
    }
}

 此处通过zuul来转发服务时都要经过此过滤器

 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。