Spring Cloud Gateway 核心功能与实战实现指南

一、核心功能架构

二、六大核心功能实现

1. 动态路由配置

application.yml 配置示例：

spring:cloud:gateway:routes:▪ id: user-serviceuri: lb://user-service  # 服务注册中心名称predicates:▪ Path=/api/users/**filters:▪ StripPrefix=1  # 去掉/api前缀

代码增强（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. 断言(Predicate)配置

常用断言类型：

routes:• id: time-routeuri: http://example.orgpredicates:◦ After=2023-01-20T17:42:47.789-07:00[America/Denver]  # 时间断言◦ Header=X-Request-Id, \d+  # 请求头正则匹配◦ Method=GET,POST  # HTTP方法◦ Query=name, .+  # 查询参数

自定义断言实现：

public class CustomPredicate implements RoutePredicateFactory<Config> {@Overridepublic Predicate<ServerWebExchange> apply(Config config) {return exchange -> {// 实现自定义逻辑return exchange.getRequest().getHeaders().containsKey("X-Special");};}
}

3. 过滤器(Filter)配置

内置过滤器示例：

filters:• AddRequestHeader=X-Request-color, blue  # 添加请求头• AddResponseHeader=X-Response-Rate, 1000  # 添加响应头• Retry=3  # 重试机制• CircuitBreaker=myCircuitBreaker  # 熔断器

自定义全局过滤器：

@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;  // 执行顺序}
}

4. 负载均衡配置

自动集成负载均衡：

spring:cloud:loadbalancer:ribbon:enabled: truegateway:routes:▪ id: product-serviceuri: lb://product-service  # lb://表示启用负载均衡predicates:▪ Path=/products/**

5. 熔断降级配置

Resilience4J熔断配置：

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", "服务暂时不可用","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个令牌redis-rate-limiter.burstCapacity: 20  # 桶容量key-resolver: "#{@userKeyResolver}"  # SpEL表达式

Key解析器实现：

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

三、高级配置技巧

1. 跨域配置

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

2. 重试机制

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

3. 请求/响应修改

filters:• RewritePath=/api/v1/(?<segment>.*), /$\{segment}  # 路径重写• SetRequestHeader=X-Request-From, Gateway  # 设置请求头• RemoveResponseHeader=Server  # 移除响应头

四、监控与调试

1. Actuator端点配置

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

访问端点：

• /actuator/gateway/routes - 查看所有路由
• /actuator/gateway/globalfilters - 查看全局过滤器
• /actuator/gateway/routefilters - 查看路由过滤器

2. 日志记录配置

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

五、安全最佳实践

1. JWT验证过滤器

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. 敏感头过滤

spring:cloud:gateway:default-filters:▪ RemoveRequestHeader=Cookie,Set-Cookie  # 禁止传递Cookie

通过以上配置和代码示例，您可以快速搭建具备完整功能的API网关。建议根据实际业务需求组合不同的路由策略和过滤器链。

关联知识

【Spring知识】Spring cloud gateway使用详解