【1.3 API服务网关（SpringCloudGateway）】Spring Cloud Gateway网关自定义拦截器实现鉴权

在Spring Cloud Gateway中，可以通过实现GatewayFilterFactory接口来创建自定义的拦截器。以下是一个简单的自定义拦截器的例子，它会在请求被路由之前打印一条日志。

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.core.Ordered;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
 
public class CustomGatewayFilterFactory implements GatewayFilterFactory, Ordered {
 
    private static final Logger log = LoggerFactory.getLogger(CustomGatewayFilterFactory.class);
 
    @Override
    public GatewayFilter apply(Object config) {
        return (exchange, chain) -> {
            log.info("Custom Gateway Filter Factory is called. Config: {}", config.toString());
            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
                log.info("Request is routed successfully");
            }));
        };
    }
 
    @Override
    public int getOrder() {
        // 定义拦截器的顺序，数字越小，优先级越高
        return 0;
    }
}

在application.yml配置文件中添加自定义拦截器：

spring:
  cloud:
    gateway:
      routes:
        - id: custom_route
          uri: https://example.org
          filters:
            - CustomGatewayFilterFactory=someConfig

在这个例子中，CustomGatewayFilterFactory是自定义的拦截器工厂，它实现了GatewayFilterFactory接口。在路由配置中，通过CustomGatewayFilterFactory指定了一个配置参数someConfig。当请求通过网关时，它会先经过自定义拦截器打印日志，然后再路由到指定的服务。