springcloud中网关zuul的过滤器zuulFilter的使用

1 介绍

Filter 的生命周期有 4 个，分别是
“PRE（前置过滤器）”：该类型的filters在Request routing到源web-service之前执行。用来实现Authentication、选择源服务地址等；
“ROUTING（路由选择）”：该类型的filters用于把Request routing到源web-service，源web-service是实现业务逻辑的服务。这里使用HttpClient请求web-service；
“POST（后置过滤器）” ：该类型的filters在ROUTING返回Response后执行。用来实现对Response结果进行修改，收集统计数据以及把Response传输会客户端。
“ERROR（错误过滤器）”：上面三个过程中任何一个出现错误都交由ERROR类型的filters进行处理。

2 配置

在微服务前面放一层网关，作用是将微服务的有关信息（比如端口）给包裹起来，不让用户直接看到，同时网关zuul还可以进行一些负载均衡的操作。
1、需求说明
在网关zuul进行微服务网址转发之前，判断用户是否登录。
2、配置注册中心Eureka
3、配置网关zuul
项目结构

（1）pom依赖

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

（2）配置application.yml

server:port: 8080
spring:application:name: service-zuulzuul:routes:mydept:path: /mydept/**serviceId: http-testignored-services: "*"eureka:client:service-url:defaultZone: http://127.0.0.1:8000/eureka/instance:instance-id: myzuul.comprefer-ip-address: true

（3）zuulFilter类

package com.xiaolun.config;import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import org.apache.commons.lang.StringUtils;
import org.springframework.cloud.netflix.zuul.filters.support.FilterConstants;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;import javax.servlet.http.HttpServletRequest;@Component
public class ZuulFilterTest extends ZuulFilter {//filter的类型，前置pre,后置post@Overridepublic String filterType() {return FilterConstants.PRE_TYPE;}//filter的执行顺序，值越小，越先执行@Overridepublic int filterOrder() {return 1;}//判断请求是否需要过滤@Overridepublic boolean shouldFilter() {System.out.println("---------进入shouldFilter----------");//举例：目标：订单服务需要过滤。当是商品服务，不需要过滤RequestContext ctx = RequestContext.getCurrentContext();HttpServletRequest request = ctx.getRequest();if (request.getRequestURI().contains("zuulTT")) { //含有zuulTT需要过滤,当路径中只有部分匹配时，也要进行过滤return true;}return false;}//请求过滤的规则@Overridepublic Object run() {System.out.println("---------进入run方法---------------");RequestContext ctx = RequestContext.getCurrentContext();HttpServletRequest request = ctx.getRequest();String token = request.getParameter("token");System.out.println("token= "+ token);if (! StringUtils.isEmpty(token)) {return null;}if (StringUtils.isEmpty(token)) { //没有携带token,不允许访问ctx.setSendZuulResponse(false);//后台会接收到401未授权代码ctx.setResponseStatusCode(HttpStatus.UNAUTHORIZED.value());//这里一定要加要给Response设置CharacterEncoding编码为UTF-8ctx.getResponse().setContentType("text/html;charset=UTF-8");ctx.setResponseBody("{\"result\":\"请您先登陆\"}");// 返回错误内容（json格式返回）}return null;}
}

（4）主启动类

package com.xiaolun;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 ZuulMain8080 {public static void main(String[] args) {SpringApplication.run(ZuulMain8080.class, args);}
}

4、测试类
（1）pom依赖

   <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--监控--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-eureka</artifactId></dependency>

（2）配置application.yml

server:port: 7000spring:application:name: http-test
eureka:client:register-with-eureka: true #将自己入驻进eurekaservice-url:defaultZone:  http://localhost:8000/eureka

（3）业务类-controller

package com.xiaolun.zuulTest;import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;@Controller
public class ZuulHello {@RequestMapping("zuulTest02")@ResponseBodypublic String zuulTest02() {return "hello zuul02";}
}

（4）主启动类

package com.xiaolun;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;@SpringBootApplication
@EnableEurekaClient
public class HttpTestMain7000 {public static void main(String[] args) {SpringApplication.run(HttpTestMain7000.class, args);}
}

5、测试
依次启动Eureka，zuul和测试类，输入下面的网址：

#http://zuul注册进Eureka的instance-id名:zuul启动的端口号/微服务名称（这里不启用）/路由转发/controller网址
http://myzuul.com:8080/mydept/zuulTest02

可以正常访问：

当我们的网址中含有zuulTT字段时（类zuulTT也算），就会被网关zuul过滤器进行过滤，我们需要在网址中增加token字段，比如：

http://myzuul.com:8080/mydept/zuulTT?token=100

否则会报错，进而弹出下面的界面：

{"result":"请您先登陆"}