1.服务网关Zuul介绍
服务网关是微服务架构中一个不可或缺的部分。通过服务网关统一向外系统提供REST API的过程中，除了具备服务路由、均衡负载功能之外，它还具备了权限控制等功能。Spring Cloud Netflix中的Zuul就担任了这样的一个角色，为微服务架构提供了前门保护的作用，同时将权限控制这些较重的非业务逻辑内容迁移到服务路由层面，使得服务集群主体能够具备更高的可复用性和可测试性。
2.为什么要用Zuul
本图摘自方志鹏的深入理解SpringCloud微服务书籍
3.Zuul服务网关使用的架构图示
4.实现Zuul的代码：
1.pom文件
<?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.xueqing.demo</groupId><artifactId>service-zuul</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><name>service-zuul</name><description>Demo project for Spring Boot</description><parent><groupId>com.xueqing.demo</groupId><artifactId>springcloud1</artifactId><version>1.0-SNAPSHOT</version></parent><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-eureka-client</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-zuul</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.46</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>
2.SpringBoot启动类开启Zuul注解
package com.xueqing.demo.servicezuul;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@EnableZuulProxy
public class ServiceZuulApplication {public static void main(String[] args) {SpringApplication.run(ServiceZuulApplication.class, args);}
}
3.实现FallbackProvider接口重写两个方法
package com.xueqing.demo.servicezuul;import com.alibaba.fastjson.JSONObject;
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;@Component
public class MyProvinder implements FallbackProvider {@Overridepublic String getRoute() {return "*";//api服务id，如果需要所有调用都支持回退，则return "*"或return null}/*** 如果请求用户服务失败，返回什么信息给消费者客户端*/@Overridepublic ClientHttpResponse fallbackResponse(String route, Throwable cause) {return new ClientHttpResponse(){@Overridepublic InputStream getBody() throws IOException {JSONObject r = new JSONObject();r.put("state", "9999");r.put("msg", "系统错误，请求失败");return new ByteArrayInputStream(r.toJSONString().getBytes("UTF-8"));}@Overridepublic HttpHeaders getHeaders() {HttpHeaders headers = new HttpHeaders();//和body中的内容编码一致，否则容易乱码headers.setContentType(MediaType.APPLICATION_JSON_UTF8);return headers;}/*** 网关向api服务请求是失败了，但是消费者客户端向网关发起的请求是OK的，* 不应该把api的404,500等问题抛给客户端* 网关和api服务集群对于客户端来说是黑盒子*/@Overridepublic HttpStatus getStatusCode() throws IOException {return HttpStatus.OK;}@Overridepublic int getRawStatusCode() throws IOException {return HttpStatus.OK.value();}@Overridepublic String getStatusText() throws IOException {return HttpStatus.OK.getReasonPhrase();}@Overridepublic void close() {}};}}
