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 转发到到 User 服务,/api/shop 转发到到 Shop 服务。Zuul 默认和 Ribbon 结合实现了负载均衡的功能。
新建Zuul项目
我们需要新建一个zuul项目来作为网关控制的项目,
因此我们有这样的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.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>
<!-- 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.funtl.hello.spring.cloud.zuul.ZuulApplication</mainClass>
</configuration>
</plugin>
</plugins>
</build>
</project>
主要是增加了zuul的依赖
在启动类中增加zuul注解
@SpringBootApplication
@EnableEurekaClient
@EnableZuulProxy
public class ZuulApplication {
public static void main(String[] args) {
SpringApplication.run(ZuulApplication.class, args);
}
}
配置application.yml
spring:
application:
name: hello-spring-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
此时在原有的服务注册中心,服务提供者,服务调用者ribbon和Feign的基础上,另外将zuul服务也启动,
此时我们会发现当访问http://localhost:8769/api/a/hi?message=HelloZuul和http://localhost:8769/api/b/hi?message=HelloZuul时在不同的ribbon和feign服务中均发生了调用
配置网关路由失败时的回调
当我们的某一个服务崩溃时,网关要负责进行回调,此时需要添加回调类
@Component
public class WebAdminFeignFallbackProvider implements FallbackProvider {
@Override
public String getRoute() {
// ServiceId,如果需要所有调用都支持回退,则 return "*" 或 return null,单个支持回调只需要加入application.name 例如 return "hello-spring-cloud-web-admin-feign"
return "*";
}
/**
* 如果请求服务失败,则返回指定的信息给调用者
* @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() {
}
@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;
}
};
}
此时如果关闭ribbon服务的话,那么访问链接会显示,会出现我们预先设置好的错误信息
增加路由过滤功能
路由过滤功能需要实现ZuulFilter,我们进行如下实现
@Component
public class LoginFilter extends ZuulFilter {
private static final Logger logger = LoggerFactory.getLogger(LoginFilter.class);
/**
* 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 {
RequestContext context = RequestContext.getCurrentContext();
HttpServletRequest request = context.getRequest();
logger.info("{} >>> {}", request.getMethod(), request.getRequestURL().toString());
String token = request.getParameter("token");
if (token == null) {
logger.warn("Token is empty");
context.setSendZuulResponse(false);
context.setResponseStatusCode(401);
try {
context.getResponse().getWriter().write("Token is empty");
} catch (IOException e) {
}
} else {
logger.info("OK");
}
return null;
}
}
几个参数的具体含义
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
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
是否需要过滤,这里是 true,需要过滤
run
过滤器的具体业务代码
此时我们访问链接
http://localhost:8769/api/b/hi?message=HelloZuul&token=123显示正常信息,我们访问http://localhost:8769/api/b/hi?message=HelloZuul会出现Token is empty的错误提示