简介

Zuul包含了对请求的路由和过滤两个最主要的功能：
其中路由功能负责将外部请求转发到具体的微服务实例上，是实现外部访问统一入口的基础而过滤器功能则负责对请求的处理过程进行干预，是实现请求校验、服务聚合等功能的基础.

Zuul和Eureka进行整合，将Zuul自身注册为Eureka服务治理下的应用，同时从Eureka中获得其他微服务的消息，也即以后的访问微服务都是通过Zuul跳转后获得。

注意：Zuul服务最终还是会注册进Eureka

官方资料

新建zuul模块

引入相关依赖

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

启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
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.yml

server:
  port: 8089
spring:
  application:
    name: spring-cloud-zuul
eureka:
  instance:
    instance-id: zuul:${server.port}
    prefer-ip-address: true
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/


#路由访问映射规则
zuul:
  routes:
    zuul.serviceId: feign-server
    zuul.path: /zuul-user-service/**
  ignored-services: "*" #忽略原真实服务名
  prefix: /felix #设置统一公共前缀
  host:
    connect-timeout-millis: 15000 #HTTP连接超时要比Hystrix的大
    socket-timeout-millis: 60000   #socket超时
  retryable: true #重试

访问 http://192.168.137.1:8089/felix/zuul-user-service/user/list

正常显示,

服务过滤

zuul不仅只是路由，并且还能过滤，做一些安全验证。继续改造工程；

import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import lombok.extern.slf4j.Slf4j;

import javax.servlet.http.HttpServletRequest;

@Component
@Slf4j
public class CustomerFilter 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 ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();
        log.info(String.format("%s >>> %s", request.getMethod(), request.getRequestURL().toString()));
        Object accessToken = request.getParameter("token");
        if (accessToken == null) {
            log.warn("token is empty");
            ctx.setSendZuulResponse(false);
            ctx.setResponseStatusCode(401);
            try {
                ctx.getResponse().getWriter().write("token is empty");
            } catch (Exception e) {
            }
            return null;
        }
        log.info("ok");
        return null;
    }
}

• 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，具体如下：
• 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：这里可以写逻辑判断，是否要过滤，本文true,永远过滤。
• run：过滤器的具体逻辑。可用很复杂，包括查sql，nosql去判断该请求到底有没有权限访问。

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 java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

public class ZuulFallback implements FallbackProvider {
    @Override
    public String getRoute() {
        //服务id，可以用* 或者 null 代表所有服务都过滤
        return "*";
    }

    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                //请求成功
                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 {
                JSONObject json =new JSONObject();
                json.put("state","501");
                json.put("msg","后台接口错误");
                return new ByteArrayInputStream(json.toJSONString().getBytes("UTF-8"));
            }

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

浏览器访问

http://192.168.137.1:8089/felix/zuul-user-service/user/list

出现 token is empty 说明zuul起到了保护的作用

添加token
再次访问

http://192.168.137.1:8089/felix/zuul-user-service/user/list?token=%22token%22

访问正常

参考

forezp