网关（Gateway）- 自定义过滤器工厂

自定义过滤工厂类

DemoGatewayFilterFactory

package com.learning.springcloud.custom;

import org.apache.commons.lang.StringUtils;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.util.Arrays;
import java.util.List;

@Component
public class DemoGatewayFilterFactory extends AbstractGatewayFilterFactory<DemoGatewayFilterFactory.Config> {

    public DemoGatewayFilterFactory() {
        super(Config.class);
    }

    public List<String> shortcutFieldOrder() {
        return Arrays.asList("name", "value");
    }

    @Override
    public GatewayFilter apply(DemoGatewayFilterFactory.Config config) {
        return new GatewayFilter() {
            public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
                String value = exchange.getRequest().getQueryParams().getFirst("name");

                if (StringUtils.isBlank(value)) {
                    // 为空 则证明是正常的请求 需要放行
                    return chain.filter(exchange);
                }
                if ("YES".equals(value)) {
                    return chain.filter(exchange);
                }
                exchange.getResponse().setStatusCode(HttpStatus.NOT_FOUND);
                return exchange.getResponse().setComplete();
            }
        };
    }

    public static class Config {
        private String name;
        private String value;

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public String getValue() {
            return value;
        }

        public void setValue(String name) {
            this.value = name;
        }
    }
}

过滤器配置说明

server:
  port: 8088
spring:
  application:
    name: api-gateway
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8847
        username: nacos
        password: nacos
    gateway:
      routes:
        - id: order_route # 路由唯一标识
          #uri: http://localhost:8020 # 需要转发的地址
          uri: lb://order-service # 需要转发的地址
          # 断言规则  用于路由规则的匹配
          predicates:
#            - Path=/order-serv/**
#            - After=2024-01-01T23:00:11.518+08:00[Asia/Shanghai]
#            - Before=2025-01-01T23:00:11.518+08:00[Asia/Shanghai]
            - Between=2024-01-01T23:00:11.518+08:00[Asia/Shanghai],2025-01-01T23:00:11.518+08:00[Asia/Shanghai]
#            - Header=X-Request-Id,\d+
#            - Host=127.0.0.1
#            - Query=name,lq
#            - Method=GET,POST
            # http://localhost:8088/order-serv/order/add  => http://localhost:8020/order-serv/order/add
            - Demo=YES
          #配置过滤器工厂
          filters:
            - StripPrefix=1 # 转发去掉第一层路径
            - AddRequestHeader=X-Request-name,tom #添加请求头
            - AddRequestParameter=color, blue # 添加请求参数
            - PrefixPath=/demo
#            - RedirectTo=302, https://www.baidu.com/ #重定向到百度
            - Demo=name,YES  # 自定义过滤工厂配置
            # http://localhost:8020/order-serv/order/add => http://localhost:8020/order/add

访问效果

• 不带name参数的请求放行

• 带name参数值不是YES的拦截,返回 not found

• 带name参数值是YES的放行

实现说明 

• 命名必须需要以 FilterFactory 结尾（约定规范）
• 继承 AbstractGatewayFilterFactory 类
• 必须为spring的组件bean（@Component）
• 必须要有内部类 Config 以及 对应的 shortcutFieldOrder 方法
• 重写 apply 方法的逻辑 （apply(DemoGatewayFilterFactory.Config config)）
• 可通过 exchange.getRequest() 获取到 ServerHttpRequest 对象
• 从而获取到请求的参数、请求方式、请求头等信息