Spring Cloud Gateway 核心功能與實戰實現指南

一、核心功能架構

二、六大核心功能實現

1. 動態路由配置

application.yml 配置示例：

spring:cloud:gateway:routes:? id: user-serviceuri: lb://user-service  # 服務注冊中心名稱predicates:? Path=/api/users/**filters:? StripPrefix=1  # 去掉/api前綴

代碼增強（Java DSL方式）：

@Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {return builder.routes().route("auth-service", r -> r.path("/auth/**").filters(f -> f.rewritePath("/auth/(?<segment>.*)", "/${segment}")).uri("lb://auth-service")).build();
}

2. 斷言(Predicate)配置

常用斷言類型：

routes:? id: time-routeuri: http://example.orgpredicates:? After=2023-01-20T17:42:47.789-07:00[America/Denver]  # 時間斷言? Header=X-Request-Id, \d+  # 請求頭正則匹配? Method=GET,POST  # HTTP方法? Query=name, .+  # 查詢參數

自定義斷言實現：

public class CustomPredicate implements RoutePredicateFactory<Config> {@Overridepublic Predicate<ServerWebExchange> apply(Config config) {return exchange -> {// 實現自定義邏輯return exchange.getRequest().getHeaders().containsKey("X-Special");};}
}

3. 過濾器(Filter)配置

內置過濾器示例：

filters:? AddRequestHeader=X-Request-color, blue  # 添加請求頭? AddResponseHeader=X-Response-Rate, 1000  # 添加響應頭? Retry=3  # 重試機制? CircuitBreaker=myCircuitBreaker  # 熔斷器

自定義全局過濾器：

@Component
public class AuthFilter implements GlobalFilter, Ordered {@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {String token = exchange.getRequest().getHeaders().getFirst("Authorization");if(!validateToken(token)){exchange.getResponse().setStatusCode(HttpStatus.UNAUTHORIZED);return exchange.getResponse().setComplete();}return chain.filter(exchange);}@Overridepublic int getOrder() {return -1;  // 執行順序}
}

4. 負載均衡配置

自動集成負載均衡：

spring:cloud:loadbalancer:ribbon:enabled: truegateway:routes:? id: product-serviceuri: lb://product-service  # lb://表示啟用負載均衡predicates:? Path=/products/**

5. 熔斷降級配置

Resilience4J熔斷配置：

spring:cloud:gateway:routes:? id: inventory-serviceuri: lb://inventory-servicepredicates:? Path=/inventory/**filters:? name: CircuitBreakerargs:name: inventoryCBfallbackUri: forward:/fallback/inventorystatusCodes: 500,503

Fallback控制器：

@RestController
public class FallbackController {@GetMapping("/fallback/inventory")public Mono<Map<String, Object>> inventoryFallback() {return Mono.just(Map.of("status", 503,"message", "服務暫時不可用","timestamp", Instant.now()));}
}

6. 限流配置

Redis令牌桶限流：

spring:redis:host: localhostcloud:gateway:routes:? id: order-serviceuri: lb://order-servicepredicates:? Path=/orders/**filters:? name: RequestRateLimiterargs:redis-rate-limiter.replenishRate: 10  # 每秒10個令牌redis-rate-limiter.burstCapacity: 20  # 桶容量key-resolver: "#{@userKeyResolver}"  # SpEL表達式

Key解析器實現：

@Bean
KeyResolver userKeyResolver() {return exchange -> Mono.just(exchange.getRequest().getQueryParams().getFirst("userId"));
}

三、高級配置技巧

1. 跨域配置

spring:cloud:gateway:globalcors:cors-configurations:'[/**]':allowedOrigins: "*"allowedMethods:? GET? POST? PUTallowedHeaders:? Content-Type

2. 重試機制

filters:? name: Retryargs:retries: 3statuses: BAD_GATEWAY,INTERNAL_SERVER_ERRORmethods: GET,POSTbackoff:firstBackoff: 10msmaxBackoff: 100msfactor: 2

3. 請求/響應修改

filters:? RewritePath=/api/v1/(?<segment>.*), /$\{segment}  # 路徑重寫? SetRequestHeader=X-Request-From, Gateway  # 設置請求頭? RemoveResponseHeader=Server  # 移除響應頭

四、監控與調試

1. Actuator端點配置

management:endpoints:web:exposure:include: gatewayendpoint:gateway:enabled: true

訪問端點：

• /actuator/gateway/routes - 查看所有路由
• /actuator/gateway/globalfilters - 查看全局過濾器
• /actuator/gateway/routefilters - 查看路由過濾器

2. 日志記錄配置

logging:level:org.springframework.cloud.gateway: DEBUGreactor.netty.http.client: DEBUG

五、安全最佳實踐

1. JWT驗證過濾器

public class JwtFilter implements GlobalFilter {@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {String token = exchange.getRequest().getHeaders().getFirst("Authorization");if (token != null && JwtUtil.validateToken(token)) {String username = JwtUtil.getUsernameFromToken(token);exchange.getRequest().mutate().header("X-User-Name", username).build();return chain.filter(exchange);}exchange.getResponse().setStatusCode(HttpStatus.UNAUTHORIZED);return exchange.getResponse().setComplete();}
}

2. 敏感頭過濾

spring:cloud:gateway:default-filters:? RemoveRequestHeader=Cookie,Set-Cookie  # 禁止傳遞Cookie

通過以上配置和代碼示例，您可以快速搭建具備完整功能的API網關。建議根據實際業務需求組合不同的路由策略和過濾器鏈。

關聯知識

【Spring知識】Spring cloud gateway使用詳解