学习微服务的路由网关zuul——路由转发和过滤器

zuul具备路由转发和过滤的功能，相似于nginx的功能。首先新建一个项目service-zuul来实现路由转发的功能。

1.路由转发功能

build.gradle文件

buildscript {
	ext {
		springBootVersion = '2.0.4.RELEASE'
	}
	repositories {
		mavenCentral()
	}
	dependencies {
		classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
	}
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
	mavenCentral()
}


ext {
	springCloudVersion = 'Finchley.SR1'
}

dependencies {
	compile('org.springframework.boot:spring-boot-starter-web')
	compile('org.springframework.cloud:spring-cloud-starter-netflix-eureka-client')
	compile('org.springframework.cloud:spring-cloud-starter-netflix-zuul')
	testCompile('org.springframework.boot:spring-boot-starter-test')
}

dependencyManagement {
	imports {
		mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
	}
}

application.yml文件

server:
  port: 8798

spring:
  application:
    name: service-zuul
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8791/eureka/

zuul:
  routes:
    api-a:
      path: /api-a/*
      serviceId: service-ribbon
    api-b:
      path: /api-b/*
      serviceId: service-feign

主方法

package com.example.servicezuul;

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 ServiceZuulApplication {

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

启动该项目，以及service-ribbon,service-feign项目，以及eureka-server项目，以及eureka-client-say-hi项目，此时的eureka注册中心是这样：

此时分别访问http://localhost:8798/api-a/hi；

以及http://localhost:8798/api-b/hi;

其响应页面都是：

以上结果代表，zuul实现了路由转发的功能，只需加上注解@EnableZuulProxy以及路由转发相关策略便可。

 

2.过滤功能

在上面项目的基础上添加一个自定义的过滤组件

MyFilter.java

package com.example.servicezuul;

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

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

@Component
public class MyFilter extends ZuulFilter {
    @Override
    public String filterType() {  //过滤器类型，一共有4种不一样周期的类型，pre:路由以前；routing:路由之时；post:表明路由以后；error:错误时调用
        return "pre";
    }

    @Override
    public int filterOrder() { //过滤器使用顺序
        return 0;
    }

    @Override
    public boolean shouldFilter() { //是否容许过滤，为true，即始终过滤
        return true;
    }

    @Override
    public Object run() throws ZuulException {  //过滤器的具体逻辑，如下的内容大体是，有test参数容许访问，没有test参数不容许访问

        RequestContext requestContext = RequestContext.getCurrentContext();
        HttpServletRequest request = requestContext.getRequest();
        Object o = request.getParameter("test");
        if (o == null) {
            requestContext.setSendZuulResponse(false);
            requestContext.setResponseStatusCode(401);
            try {
                requestContext.getResponse().getWriter().write("test is empty");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }


}

运行结果比较：

 

以上结果代表，过滤器已经产生做用了。