springcloud(八)--路由网关zuul (原创)

如题，本篇我们介绍下spring cloud中的路由组件zuul。

zuul是什么？

在微服务架构中,需要几个关键的组件,服务注册与发现、服务消费、负载均衡、断路器、智能路由、配置管理等,zuul就是起到只能路由(过滤)功能的组件。

zuul具有以下的功能。 

Authentication  
Insights   
Stress Testing
Canary Testing
Dynamic Routing
Service Migration
Load Shedding
Security
Static Response handling
Active/Active traffic management

我们新建两个maven工程sim-serviceA 、 sim-serviceB ,再建立zuul网关工程sim-zuul 。

sim-serviceA 工程  :

application.yml 

server:
  port: 6001
  context-path: /
  
  
#devtool 热加载工具
spring:
  devtools:
    restart:
      enabled: true
      exclude: resources/**
#spring应用名称  、实例id配置
  application:
    name: sim-serviceA
    
eureka: 
  instance: 
    hostname: localhost  #eureka客户端主机实例名称
    prefer-ip-address: true
  client: 
    service-url: 
      defaultZone: http://localhost:8761/eureka  
         

pom.xml中引入

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

package com.tingcream.simServiceA;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@EnableEurekaClient
@SpringBootApplication
public class SimServiceAApp {
	public static void main(String[] args) {
        SpringApplication.run(SimServiceAApp.class, args);
    }
}

package com.tingcream.simServiceA.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;


@RestController
public class ServiceAController {
	
	@Value("${spring.application.name}")
	private String applicationName;
	@Value("${server.port}")
	private String port ;

	@GetMapping("/")
	public String index(){
		 return "ServiceAController: 你好,我是"+applicationName+",服务端口:"+port;
	}
	
	@GetMapping("/hi")
	public String hi(String name){
		 return "ServiceAController: hi "+name+",我是"+applicationName+",服务端口:"+port;
	}
	
}

sim-serviceB 工程  :

application.yml 

server:
  port: 6002
  context-path: /
  
  
#devtool 热加载工具
spring:
  devtools:
    restart:
      enabled: true
      exclude: resources/**
#spring应用名称  、实例id配置
  application:
    name: sim-serviceB
    
eureka: 
  instance: 
    hostname: localhost  #eureka客户端主机实例名称
    prefer-ip-address: true
  client: 
    service-url: 
      defaultZone: http://localhost:8761/eureka  
         

pom.xml中引入

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

package com.tingcream.simServiceB;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
 
@EnableEurekaClient
@SpringBootApplication
public class SimServiceBApp {
	
	public static void main(String[] args) {
        SpringApplication.run(SimServiceBApp.class, args);
    }
	
}

package com.tingcream.simServiceB.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;


@RestController
public class ServiceBController {
	
	@Value("${spring.application.name}")
	private String applicationName;
	@Value("${server.port}")
	private String port ;

	@GetMapping("/")
	public String index(){
		 return "ServiceBController: 你好,我是"+applicationName+",服务端口:"+port;
	}

	@GetMapping("/hi")
	public String hi(String name){
		 return "ServiceBController: hi "+name+",我是"+applicationName+",服务端口:"+port;
	}

}

application.yml

server:
  port: 80
  context-path: /
  

spring: 
  application:
    name: sim-zuul
    
eureka: 
  instance: 
    hostname: localhost  #eureka客户端主机实例名称
    prefer-ip-address: true
  client: 
    service-url: 
      defaultZone: http://localhost:8761/eureka  
    
zuul:
  ignoredServices: sim-provider
  routes:
    serviceA: 
      path: /serviceA/**
      serviceId: sim-serviceA
    serviceB:
      path: /serviceB/**
      serviceId: sim-serviceB

pom.xml中引入

 <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    

springboot启动类

package com.tingcream.simZuul;
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;
 

@EnableZuulProxy
@EnableEurekaClient
@SpringBootApplication
public class SimZuulApp {
  
	public static void main(String[] args) {
        SpringApplication.run(SimZuulApp.class, args);
    }
	
	
}

依次启动sim-eureka  、sim-zuul 、 sim-serviceA 、 sim-serviceB，访问http://localhost/8761

注： 由于使用到了zuul网关(提供外部用户访问的入口)，我们将sim-zuul的端口设置为了80，将sim-consumer应用的端口修改为了6000

zuul有一些默认的路由配置规则，如果映射规则我们什么都不写，zuul也给我们提供了一套默认的配置规则，默认配置规则如下：
zuul.routes.serviceXXX.path=/serviceXXX/**
zuul.routes.serviceXXX.serviceId=serviceXXX

因此，即使我们没有配置 sim-consumer服务的路由规则，当我们请求 http://localhost/sim-consumer/student/list 也是可以访问成功的。还有点需要注意的是，zuul默认会给所有注册到eureka server上的应用配置默认的映射路由。而sim-provider是我们内部系统的一个微服务，是不能让外部用户直接访问，因而可以使用zuul.ignoredServices= xxx 来忽略掉特定服务的路由映射。如果使用zuul.ignoredServices= '*' 则表示忽略所有的微服务的路由映射，设置后我们需要再手动添加需要映射的服务。

------------------

zuul中的过滤器 ，例如自定义过滤器MyFilter，对所有请求进行拦截，判断是否有传token参数。 

package com.tingcream.simZuul;

import javax.servlet.http.HttpServletRequest;

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{
	 
	@Override
	public Object run() throws ZuulException {
		   RequestContext ctx = RequestContext.getCurrentContext();
	        HttpServletRequest request = ctx.getRequest();
	        System.out.println("请求方法："+request.getMethod());
	        System.out.println("请求URL："+request.getRequestURL().toString());
	        Object accessToken = request.getParameter("token");//获取param中 token， token不能为空
	        if(accessToken == null) {
	            ctx.setSendZuulResponse(false);
	            ctx.setResponseStatusCode(401);
	            try {
	                ctx.getResponse().getWriter().write("token is empty");
	            }catch (Exception e){
	            	e.printStackTrace();
	            }
	            return null;
	        }
	        System.out.println("token值为:"+accessToken);
	        System.out.println("zuul 中 MyFilter： 过滤器执行通过 ");
	        return null;
	}

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

	@Override
	public int filterOrder() {
		return 0;
	}
	@Override
	public String filterType() {
		return "pre";
	}
    
}

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： 是否要过滤，true过滤，false不过滤
run：过滤器的具体逻辑。 

浏览器访问  http://localhost/serviceA/hi?name=小明&token=1212  ，http://localhost/serviceB/?token=1111 ，如果没加token参数则无法成功访问

关于zuul的更多配置信息，可以参见官网文档

http://cloud.spring.io/spring-cloud-static/Edgware.SR4/single/spring-cloud.html 

或者 http://projects.spring.io/spring-cloud/spring-cloud.html#_router_and_filter_zuul