Spring Cloud(Finchley.RCI) (八) Spring Cloud使用路由网关统一访问接口

使用路由网关统一访问接口

在微服务架构中, 需要几个基础的服务治理组件, 包括服务注册与发现, 服务消费, 负载均衡, 熔断器, 智能路由, 配置管理等。由这几个基础组件相互协作, 共同组建了一个简单的微服务服务系统。

 

在Spring Cloud微服务系统中, 一种常见的负载均衡方式是, 客户端的请求首先经过负载均衡(Zuul, Nginx), 再到达服务网关(Zuul集群), 然后再到具体的服务。服务统一注册到高可用的服务注册中心集群, 服务的所有配置文件由配置服务管理,  配置服务的配置文件放在Git仓库, 方便开发人员随时配置。

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/api/user转发到User服务, /api/shop转发到Shop服务。Zuul默认和Ribbon结合实现了负载均衡的功能。

创建路由网关

pom

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.funtl</groupId>
        <artifactId>hello-spring-cloud-dependencies</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../hello-spring-cloud-dependencies/pom.xml</relativePath>
    </parent>

    <artifactId>hello-spring-cloud-zuul</artifactId>
    <packaging>jar</packaging>

    <name>hello-spring-cloud-zuul</name>
    <url>http://www.funtl.com</url>
    <inceptionYear>2018-Now</inceptionYear>

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

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

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

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

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

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.funtl.hello.spring.cloud.zuul.ZuulApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Application

增加@EnableZuulProxy注解开启Zuul功能

package com.funtl.hello.spring.cloud.zuul;

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;

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

application.xml

设置端口号: 8769

增加Zuul配置

spring:
  application:
    name: hello-spring-cloud-cloud-zuul
server:
  port: 8769
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
zuul:
  routes:
    api-a:
      path: /api/a/**
      serviceId: hello-spring-cloud-web-admin-ribbon
    api-b:
      path: /api/b/**
      serviceId: hello-spring-cloud-web-admin-feign

路由说明

以/api/a开头的请求都转发给hello-spring-cloud-web-admin-ribbon服务

以/api/b开头的请求都转发给hello-spring-cloud-web-admin-feign服务

测试访问

依次运行EurekaApplication, ServiceAdminApplication, WebAdminRibbonApplication, WebAdminFeignAppilcation, ZuulApplication

访问http://localhost:8769/api/a/hi?message=HelloZuul

访问http://localhost:8769/api/b/hi?message=HelloZuul

 

配置网关路由失败时的回调

package com.funtl.hello.spring.cloud.zuul.provider;

import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
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.util.HashMap;
import java.util.Map;

@Component
public class WebAdminFeignFallbackProvider implements FallbackProvider{
    @Override
    public String getRoute() {
        return "hello-spring-cloud-web-admin-feign";
    }

    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.OK;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.OK.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.OK.getReasonPhrase();
            }

            @Override
            public void close() {

            }

            @Override
            public InputStream getBody() throws IOException {
                ObjectMapper objectMapper=new ObjectMapper();
                Map<String, Object> map=new HashMap<>();
                map.put("statua", 200);
                map.put("message", "Cannot connect, please check network");
                return new ByteArrayInputStream(objectMapper.writeValueAsString(map).getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                HttpHeaders headers=new HttpHeaders();
                headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
                return headers;
            }
        };
    }
}

使用路由网关的服务过滤功能

Zuul不仅仅只是路由, 还有很多强大的功能

创建服务过滤器

继承ZuulFilter类并在类上增加@Component注解就可以使用服务过滤功能了

package com.funtl.hello.spring.cloud.zuul.filter;

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

@Component
public class LoginFilter extends ZuulFilter{
    @Override
    public String filterType() {
        return "pre";
    }

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

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

    @Override
    public Object run() throws ZuulException {
        RequestContext currentContext=RequestContext.getCurrentContext();
        HttpServletRequest request = currentContext.getRequest();
        String token = request.getParameter("token");
        if(token == null){
            currentContext.setSendZuulResponse(false);
            currentContext.setResponseStatusCode(401);
            try {
                HttpServletResponse response = currentContext.getResponse();
                response.setContentType("text/html;charset=utf-8");
                currentContext.getResponse().getWriter().write("illegal request");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return null;
    }
}