Spring Cloud Zuul
Zuul负责路由转发和过滤
总览
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系统。一个简单的微服务系统如下图：
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、Ngnix），再到达服务网关（Zuul 集群），然后再到具体的服。服务统一注册到高可用的服务注册中心集群，服务的所有的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，方便开发人员随时改配置。
创建Zuul转发
配置依赖和完善工程结构
pom.xml
<?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>
<parent>
<groupId>com.outlook.liufei32</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>1.0.0-SNAPSHOT</version>
<relativePath>../spring-cloud-dependencies/pom.xml</relativePath>
</parent>
<artifactId>spring-cloud-zuul</artifactId>
<packaging>jar</packaging>
<name>spring-cloud-zuul</name>
<url></url>
<inceptionYear>2019-Now</inceptionYear>
<dependencies>
<!-- Spring Boot Begin -->
<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>
<!-- Spring Boot End -->
<!-- Spring Cloud Begin -->
<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>
<!-- Spring Cloud End -->
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<mainClass>com.outlook.liufei32.spring.cloud.zuul.ZuulApplication</mainClass>
</configuration>
</plugin>
</plugins>
</build>
</project>
application.yml
spring:
application:
name: spring-cloud-zuul
server:
port: 8769
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
zuul:
routes: #配置路由节点
api-a:
path: /api/a/** #**即全目录匹配
serviceId: spring-cloud-web-admin-ribbon #以 /api/a 开头的请求都转发给 hello-spring-cloud-web-admin-ribbon
api-b:
path: /api/b/**
serviceId: spring-cloud-web-admin-feign #以 /api/b 开头的请求都转发给 hello-spring-cloud-web-admin-feign
启动类注解
package com.outlook.liufei32.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);
}
}
自称Zuul基本配置完成，启动访问路径
http://localhost:8769/api/a/hi?message=HelloZuul
就能看到对应的结果
Hi，your message is :"HelloZuul" i am from port：8763
创建失败回调
package com.outlook.liufei32.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() {
//返回你需要为哪个微服务提供回退
// ServiceId，如果需要所有调用都支持回退，则 return "*" 或 return null
return "spring-cloud-web-admin-feign";
}
/**
* 路由 hello-spring-cloud-web-admin-feign 失败时的回调
* @param route
* @param cause
* @return
*/
@Override
public ClientHttpResponse fallbackResponse( String route, Throwable cause ) {
return new ClientHttpResponse() {
/**
* 网关向 api 服务请求失败了，但是消费者客户端向网关发起的请求是成功的，
* 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
* @return
* @throws IOException
*/
@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() {
}
//返回流，内容就是字符串json自定义的内容
@Override
public InputStream getBody() throws IOException {
ObjectMapper objectMapper = new ObjectMapper();
Map<String, Object> map = new HashMap<>();
map.put("status", 200);
map.put("message", "无法连接，请检查您的网络");
return new ByteArrayInputStream(objectMapper.writeValueAsString(map).getBytes("UTF-8"));
}
@Override
public HttpHeaders getHeaders() {
HttpHeaders headers = new HttpHeaders();
// 和 getBody 中的内容编码一致
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
return headers;
}
};
}
}
创建服务过滤
继承 ZuulFilter 类并在类上增加 @Component 注解就可以使用服务过滤功能，（在servlet中继承的是fliter，springMVC继承的是interceptorhandler）
创建ZuulFilter过滤类，并@Component
代码详细：
package com.outlook.liufei32.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 {
/**
* 配置过滤类型，有四种不同生命周期的过滤器类型
* 1. pre：路由之前
* 2. routing：路由之时
* 3. post：路由之后
* 4. error：发送错误调用
* @return
*/
@Override
public String filterType() {
return "pre";
}
/**
* 配置过滤的顺序
* @return
*/
@Override
public int filterOrder() {
return 0;
}
/**
* 配置是否需要过滤：true/需要，false/不需要
* @return
*/
@Override
public boolean shouldFilter() {
return true;
}
/**
* 过滤器的具体业务代码
* @return
* @throws ZuulException
*/
@Override
public Object run() throws ZuulException {
//从请求中获取请求上下文RequestContext
RequestContext context = RequestContext.getCurrentContext();
//从上下文中获取HttpServletRequest，就是传统的servlet HttpServletRequest
HttpServletRequest request = context.getRequest();
//获取请求的参数，这里模拟一个请求参数令牌
String token = request.getParameter("token");
if (null == token) {
//如果令牌为空则在zuul的请求中设置不发送请求
context.setSendZuulResponse(false);
context.setResponseStatusCode(401);
try {
//从上下文获得response，并设置类型和编码
HttpServletResponse response = context.getResponse();
response.setContentType("text/html;charset=utf-8");
//向请求响应流中写入内容
response.getWriter().write("非法请求");
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
}
访问
http://localhost:8769/api/a/hi?message=swagger
结果：
非法请求
带上token参数则正常访问
http://localhost:8769/api/a/hi?message=swagger&token=124
结果：
Hi，your message is : swagger i am from port : 8763
本博客为Swagger-Ranger的笔记分享，文章会持续更新
文中源码地址： https://github.com/Swagger-Ranger
欢迎交流指正，如有侵权请联系作者确认删除： liufei32@outlook.com
来源：https://www.cnblogs.com/Swagger-Ranger/p/10671522.html