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