16.Spring-Cloud-Zuul之请求过滤

public abstract class ZuulFilter implements IZuulFilter, Comparable<ZuulFilter> {


    private final DynamicBooleanProperty filterDisabled =
            DynamicPropertyFactory.getInstance().getBooleanProperty(disablePropertyName(), false);


    /**
     * to classify a filter by type. Standard types in Zuul are "pre" for pre-routing filtering,
     * "route" for routing to an origin, "post" for post-routing filters, "error" for error handling.
     * We also support a "static" type for static responses see  StaticResponseFilter.
     * Any filterType made be created or added and run by calling FilterProcessor.runFilters(type)
     *//抽象方法
     * @return A String representing that type
     */
    abstract public String filterType();


    /**
     * filterOrder() must also be defined for a filter. Filters may have the same  filterOrder if precedence is not
     * important for a filter. filterOrders do not need to be sequential.
     *  //抽象方法
     * @return the int order of a filter
     */
    abstract public int filterOrder();

public interface IZuulFilter {
    /**
     * a "true" return from this method means that the run() method should be invoked
     *
     * @return true if the run() method should be invoked. false will not invoke the run() method
     */
    boolean shouldFilter();


    /**
     * if shouldFilter() is true, this method will be invoked. this method is the core method of a ZuulFilter
     *
     * @return Some arbitrary artifact may be returned. Current implementation ignores it.
     */
    Object run();


}

<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>905.spring-cloud</groupId>
<artifactId>zuul-filter</artifactId>
<packaging>jar</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>spring-cloud Maven Webapp</name>
<url>http://maven.apache.org</url>
<!--springboot采用1.5.x 对应springcloud版本为 Dalston -->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath />
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Dalston.RELEASE</spring-cloud.version>
</properties>

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


</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<!-- 这样变成可执行的jar -->
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

package com.niugang.config;
import javax.servlet.http.HttpServletRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
public class AccessFilter extends ZuulFilter {
private final Logger logger = LoggerFactory.getLogger(AccessFilter.class);
@Override
public boolean shouldFilter() {
return true;
}
@Override
public String filterType() {
return "pre";
}
@Override
public int filterOrder() {
return 0;
}
@Override
public Object run() {
     RequestContext ctx = RequestContext.getCurrentContext();
     HttpServletRequest request = ctx.getRequest();
     logger.info("send  {} request to {} ",request.getMethod(),request.getRequestURL().toString());
     String accessToken = request.getParameter("accessToken");
     if(accessToken==null) {
    logger.warn("access token is empty");
    ctx.setSendZuulResponse(false);
    ctx.setResponseStatusCode(401);
ctx.setResponseBody("no power");
    return  null;
     }
     logger.info("access token ok");
return null;
}
  
}