<7>springcloud中使用zuul网关实现反向代理和zuul过滤器

<parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>2.0.3.RELEASE</version>
  </parent>
  <!-- 管理依赖 -->
  <dependencyManagement>
  <dependencies>
    <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-dependencies</artifactId>
    <version>Finchley.RELEASE</version>
    <type>pom</type>
    <scope>import</scope>
    </dependency>
  </dependencies>
  </dependencyManagement>
  <dependencies>
  <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-config</artifactId>
  </dependency>
  <!-- SpringBoot整合eureka客户端 -->
  <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
  </dependency>
  </dependencies>
  <!-- 注意： 这里必须要添加， 否者各种依赖有问题 -->
  <repositories>
  <repository>
    <id>spring-milestones</id>
    <name>Spring Milestones</name>
    <url>https://repo.spring.io/libs-milestone</url>
    <snapshots>
    <enabled>false</enabled>
    </snapshots>
  </repository>
  </repositories>
application.yml
###注册 中心
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8100/eureka/
server:
  port: 80
###网关名称
spring:
  application:
    name: service-zuul
### 配置网关反向代理    
zuul:
  routes:
    api-a:
     ### 以 /api-member/访问转发到会员服务
      path: /api-member/**
      ###要转发服务的别名
      serviceId: app-vhukze-member
    api-b:
        ### 以 /api-order/访问转发到订单服务
      path: /api-order/**
      serviceId: app-vhukze-order

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 ZuulApp {
  public static void main(String[] args) {
  SpringApplication.run(ZuulApp.class, args);
  }
}

import javax.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
@Component
public class TokenFilter extends ZuulFilter{
  //编写过滤器拦截业务代码
  public Object run() throws ZuulException {
  // TODO Auto-generated method stub
  //案例：拦截所有服务接口，判断服务接口上是否传有UserToken类型参数
  RequestContext currentContext = RequestContext.getCurrentContext();
  HttpServletRequest request = currentContext.getRequest();
  String token = request.getParameter("userToken");
  if(StringUtils.isEmpty(token)) {
    //不会继续执行，直接响应给客户端
    currentContext.setSendZuulResponse(false);
    //响应的内容
    currentContext.setResponseBody("userToken is null");
  }
  return null;
  }
  //过滤器是否执行，可以添加一些逻辑，当满族条件时执行过滤器
  public boolean shouldFilter() {
  // TODO Auto-generated method stub
  return true;
  }
  //过滤器执行顺序，当一个请求在同一个阶段有过个过滤器时，多个过滤器的执行顺序
  @Override
  public int filterOrder() {
  // TODO Auto-generated method stub
  return 0;
  }
  //过滤器类型 pre是请求前执行
//  pre：在请求被转发之前，执行过滤器
//  **route：**过滤器可以处理实际的请求转发
//  post：在请求被转发之后，执行过滤器
//  error：在请求被转发时发生错误，执行过滤器
  @Override
  public String filterType() {
  // TODO Auto-generated method stub
  return "pre";
  }
}