SpringCloud超详细讲解微服务网关Zuul

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-WEB</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!-- feign -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!-- zuul路由 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>

public class MyZuulFilter extends ZuulFilter {
//    pre ：可以在请求被路由之前调用
//    route ：在路由请求时候被调用
//    post ：在route和error过滤器之后被调用
//    error ：处理请求时发生错误时被调用
    @Override
    public String filterType() {
        return "pre";// 前置过滤器
    }
    //通过int值来定义过滤器的执行顺序,优先级为0，数字越大，优先级越低
    @Override
    public int filterOrder() {
        return 0;
    }
    //返回一个boolean类型来判断该过滤器是否要执行，所以通过此函数可实现过滤器的开关
    @Override
    public boolean shouldFilter() {
        return true;//此处为true，说明需要过滤
    }
    //过滤器的具体逻辑。
    @Override
    public Object run() throws ZuulException {
        // 获取上下文
        RequestContext currentContext = RequestContext.getCurrentContext();
        httpservletRequest request = currentContext.getRequest();
        String accessToken = request.getParameter("accessToken");
        if (StringUtils.isEmpty(accessToken)) {
            //setSendZuulResponse(false)令zuul过滤该请求，不进行路由
            currentContext.setSendZuulResponse(false);
            //设置返回的错误码
            currentContext.setResponseStatusCode(401);
            currentContext.setResponseBody("AccessToken is null");
            return null;
        }
        System.out.println("获取到AccessToken为:"+accessToken);
        // 否则正常执行业务逻辑.....
        return null;
    }
}

@EnableZuulProxy
@EnableEurekaClient
@SpringBootApplication
public class ZuulApplication {
    public static void main(String[] args) {
        SpringApplication.run(ZuulApplication.class, args);
    }
}