Spring Cloud Gateway 全栈指南：核心原理、内置组件详解与集群化实战

spring:
  cloud:
    gateway:
      routes:
        - id: path_route
          uri: https://example.org
          predicates:
            - Path=/red/{segment} # 匹配 /red/1, /red/blue 等
            - Method=GET
            - Query=color, red # 且查询参数 color 必须为 red

filters:
  - StripPrefix=1 # 去除第一层路径
  - AddRequestHeader=X-Request-Source, Gateway
  - Retry=retries=3, statuses=503

import org.springframework.cloud.gateway.handler.predicate.AbstractRoutePredicateFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import java.time.LocalDateTime;
import java.util.function.Predicate;

/**
 * 自定义断言工厂：TimeRangeRoutePredicateFactory
 * 命名规范：类名必须以 RoutePredicateFactory 结尾，配置时使用前缀 TimeRange
 */
@Component
public class TimeRangeRoutePredicateFactory extends AbstractRoutePredicateFactory<TimeRangeRoutePredicateFactory.Config> {

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

    /**
     * 配置类：接收 YAML 中的参数
     */
    public static class Config {
        private String startTime; // 格式 HH:mm:ss
        private String endTime;   // 格式 HH:mm:ss
        // Getter and Setter...
    }

    @Override
    public Predicate<ServerWebExchange> apply(Config config) {
        return exchange -> {
            LocalDateTime now = LocalDateTime.now();
            int currentTotalMinutes = now.getHour() * 60 + now.getMinute();
            
            // 简单解析配置的时间字符串
            String[] startParts = config.getStartTime().split(":");
            String[] endParts = config.getEndTime().split(":");
            
            int startTotalMinutes = Integer.parseInt(startParts[0]) * 60 + Integer.parseInt(startParts[1]);
            int endTotalMinutes = Integer.parseInt(endParts[0]) * 60 + Integer.parseInt(endParts[1]);

            // 判断当前时间是否在配置范围内
            return currentTotalMinutes >= startTotalMinutes && currentTotalMinutes <= endTotalMinutes;
        };
    }
}

predicates:
  - TimeRange=09:00,18:00 # 仅在9点到18点间生效

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

/**
 * 自定义全局过滤器：AuthGlobalFilter
 */
@Component
public class AuthGlobalFilter implements GlobalFilter, Ordered {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        // 1. Pre 阶段：获取 Token
        String token = exchange.getRequest().getHeaders().getFirst("Authorization");

        // 2. 业务逻辑：简单鉴权
        if (token == null || !token.startsWith("Bearer ")) {
            // 鉴权失败，直接返回 401，中断后续过滤器链
            exchange.getResponse().setStatusCode(HttpStatus.UNAUTHORIZED);
            return exchange.getResponse().setComplete();
        }

        // 3. 传递请求：将用户信息放入 exchange 属性，供下游服务使用
        exchange.getAttributes().put("userId", "user_123");
        
        // 4. 继续执行后续过滤器
        return chain.filter(exchange).then(Mono.fromRunnable(() -> {
            // Post 阶段：响应返回后的逻辑
            System.out.println("全局过滤器：响应已返回");
        }));
    }

    @Override
    public int getOrder() {
        // 返回值越小，优先级越高。鉴权通常需要在最前面执行
        return -1; 
    }
}

spring:
  redis:
    host: 192.168.1.100
    port: 6379
  cloud:
    gateway:
      routes:
        - id: limited_route
          uri: lb://my-service
          filters:
            - name: RequestRateLimiter
              args:
                redis-rate-limiter.replenishRate: 10 # 每秒填充10个令牌
                redis-rate-limiter.burstCapacity: 20 # 桶容量20
                key-resolver: "#{@ipKeyResolver}" # 按IP限流