自定义指定路由上的Gateway过滤器工厂详解

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

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractNameValueGatewayFilterFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
@Slf4j
@Component
//自定义过滤器工厂的名字要以GatewayFilterFactory结尾，只需在前面加个前缀，并把前缀配到配置文件里
public class PreLogGatewayFilterFactory extends AbstractNameValueGatewayFilterFactory {
    @Override
    public GatewayFilter apply(NameValueConfig config) {
        return ((exchange, chain) -> {
            //配置上写的参数用config.getName(),config.getValue()来拿
            //config.getName()拿到的是a,config.getValue()拿到的是b
            log.info("请求进来了,参数:{},{}",config.getName(),config.getValue());
            //Request.mutate后可以修改请求，需改后build()
            ServerHttpRequest modifiedRequest = exchange.getRequest().mutate().build();
            //把修改后的Request给Exchange
            ServerWebExchange modifiedExchange = exchange.mutate().request(modifiedRequest).build();
            //继续下一个过滤器
            return chain.filter(modifiedExchange);
        });
    }
}

spring:
  application:
    name: gateway
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
    gateway:
      discovery:
        locator:
          enabled: true #让gateway在nacos上找微服务
      routes:
        - id: before_route
          uri: lb://user-center #lb :nacos上的微服务
          predicates:
            - MyTimeBetween=上午9:00,下午11:00 #指定一个路由规则,这里的MyTimeBetween是自定义的，可以使用spring-cloud-gateway自带的。
          filters:
            - PreLog=a,b #写前缀即可，后面是传给工厂的参数