PcLGXNjMTdiFVKTrElCl__DSC2245

Dalaoyang

Welcome to Us !

路由网关---zuul


Zuul:Zuul 是在云平台上提供动态路由,监控,弹性,安全等边缘服务的框架。Zuul 相当于是设备和 Netflix 流应用的 Web 网站后端所有请求的前门。

在微服务盛行的时代,客户端与系统之间的交互基本上如下图:

客户端想要请求到服务,首先请求到zuul网关,然后zuul网管将请求分发到对应的服务去。

新建一个springcloud_zuul(8766),pom文件加入zuul依赖,pom文件完整代码如下:

<?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.dalaoyang</groupId>
    <artifactId>springcloud_zuul</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springcloud_zuul</name>
    <description>springcloud_zuul</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.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>Edgware.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <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>${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>

然后在启动类上添加@EnableZuulProxy启动zuul,完整代码如下:

package com.dalaoyang;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableZuulProxy
public class SpringcloudZuulApplication {

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

}

在配置文件加入如下配置:

##端口号
server.port=8766

##服务名称
spring.application.name=service-zuul

##注册中心地址
eureka.client.service-url.defaultZone=http://eureka.dalaoyang.cn/eureka/


##zuul路由转发 service-a转发到service_ribbon
zuul.routes.service-a.path=/service-a/**

zuul.routes.service-a.service-id=service_ribbon

##zuul路由转发 service-b转发到service
zuul.routes.service-b.path=/service-b/**

zuul.routes.service-b.service-id=service

然后分别启动之前service(8762),service_ribbon(8764)和springcloud_zuul(8766)。

先看一下http://eureka.dalaoyang.cn,如下:

然后在浏览器上分别访问http://localhost:8766/service-a,如下

http://localhost:8766/service-b,如下

zuul网关的简单配置到这里基本上完成了。

然后介绍一个zuul的过滤器,新建一个过滤器的类RequestLogFilter,这个类需要继承ZuulFilter,需要实现几个方法。

filterType:这个方法返回过滤器的类型,pre(路由前执行),route(路由中执行),post(路由后执行),error(发生错误后执行)

filterOrder:返回一个int来指定过滤器的执行顺序

shouldFilter:返回boolean值来决定过滤器是否执行,true执行,false不执行。

run:过滤器要执行的操作。

本项目中过滤器代码如下:

package com.dalaoyang.filter;

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

import javax.servlet.http.HttpServletRequest;


/**
 * @author dalaoyang
 * @Description
 * @project springcloud_learn
 * @package com.dalaoyang.filter
 * @email yangyang@dalaoyang.cn
 * @date 2018/4/22
 */
public class RequestLogFilter extends ZuulFilter {

    Logger logger = LoggerFactory.getLogger(RequestLogFilter.class);

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

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

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

    @Override
    public Object run() {
        RequestContext requestContext = RequestContext.getCurrentContext();
        HttpServletRequest httpServletRequest = requestContext.getRequest();
        logger.info("请求路径:"+httpServletRequest.getRequestURL().toString());
        return null;
    }
}

修改一下启动类:

package com.dalaoyang;

import com.dalaoyang.filter.RequestLogFilter;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@EnableZuulProxy
public class SpringcloudZuulApplication {

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

	@Bean
	public RequestLogFilter requestLogFilter(){
		return new RequestLogFilter();
	}
}

在重启项目,访问http://localhost:8766/service-a,然后看控制台可以看到如下图:

有时会出现这样的情况,比如本文的service实例down了,如下图这种情况

那么在访问,就会无法转发,其实zuul也提供了失败回调的方法。
新建一个ServiceFallback类实现ZuulFallbackProvider接口,需要重写2个方法。

其中getRoute方法中可以指定为哪个微服务回退,*为所有服务。

代码如下:

package com.dalaoyang.fallback;

import org.springframework.cloud.netflix.zuul.filters.route.ZuulFallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;

/**
 * @author dalaoyang
 * @Description
 * @project springcloud_learn
 * @package com.dalaoyang.fallback
 * @email yangyang@dalaoyang.cn
 * @date 2018/4/22
 */
@Component
public class ServiceFallback implements ZuulFallbackProvider {

    @Override
    public String getRoute() {
        return "*";
    }

    @Override
    public ClientHttpResponse fallbackResponse() {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.OK;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return this.getStatusCode().value();
            }

            @Override
            public String getStatusText() throws IOException {
                return this.getStatusCode().getReasonPhrase();
            }

            @Override
            public void close() {

            }

            @Override
            public InputStream getBody() throws IOException {
                return new ByteArrayInputStream("当前访问服务不可用!".getBytes());
            }

            @Override
            public HttpHeaders getHeaders() {
                HttpHeaders httpHeaders = new HttpHeaders();
                MediaType mediaType = new MediaType("application", "json",
                        Charset.forName("UTF-8"));
                httpHeaders.setContentType(mediaType);
                return httpHeaders;
            }
        };
    }
}

重启项目,访问http://localhost:8766/service-a如下图所示:

源码下载 :大老杨码云

个人网站:https://www.dalaoyang.cn





标签: SPRINGCLOUD