创建 gateway-server-sentinel 项目。
添加依赖单独使用添加 sentinel-spring-cloud-gateway-adapter 依赖即可。
若想跟 Sentinel Starter 配合使用，需要加上 spring-cloud-alibaba-sentinel-gateway 依赖来让 spring-cloud-alibaba-sentinel-gateway 模块里的 Spring Cloud Gateway 自动化配置类生效。
同时请将 spring.cloud.sentinel.filter.enabled 配置项置为 false（若在网关流控控制台上看到了 URL 资源，就是此配置项没有置为 false）。
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 "> <!-- 继承父依赖 --> <parent> <artifactId>gateway-demo</artifactId> <groupId>com.example</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>gateway-server-sentinel</artifactId> <!-- 项目依赖 --> <dependencies> <!-- spring cloud gateway 依赖 --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-gateway</artifactId> </dependency> <!-- spring cloud alibaba nacos discovery 依赖 --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <!-- 单独使用 --> <!-- sentinel gateway adapter 依赖 --> <dependency> <groupId>com.alibaba.csp</groupId> <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId> </dependency> <!-- 和 Sentinel Starter 配合使用 --> <!-- <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-alibaba-sentinel-gateway</artifactId> </dependency> --> </dependencies> </project> 配置文件 server: port: 9001 # 端口 spring: application: name: gateway-server-sentinel # 应用名称 cloud: sentinel: filter: enabled: false gateway: discovery: locator: # 是否与服务发现组件进行结合，通过 serviceId 转发到具体服务实例。 enabled: true # 是否开启基于服务发现的路由规则 lower-case-service-id: true # 是否将服务名称转小写 # 路由规则 routes: - id: order-service # 路由 ID，唯一 uri: lb://order-service # 目标 URI，lb:// 根据服务名称从注册中心获取服务请求地址 predicates: # 断言（判断条件） # 匹配对应 URI 的请求，将匹配到的请求追加在目标 URI 之后 - Path=http://www.likecs.com/order/** 限流规则配置类使用时只需注入对应的 SentinelGatewayFilter 实例以及 SentinelGatewayBlockExceptionHandler 实例即可。
GatewayConfiguration.java
package com.example.config; import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule; import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager; import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter; import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler; import org.springframework.beans.factory.ObjectProvider; import org.springframework.cloud.gateway.filter.GlobalFilter; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.core.Ordered; import org.springframework.core.annotation.Order; import org.springframework.http.codec.ServerCodecConfigurer; import org.springframework.web.reactive.result.view.ViewResolver; import javax.annotation.PostConstruct; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Set; /** * 限流规则配置类 */ @Configuration public class GatewayConfiguration { private final List<ViewResolver> viewResolvers; private final ServerCodecConfigurer serverCodecConfigurer; /** * 构造器 * * @param viewResolversProvider * @param serverCodecConfigurer */ public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider, ServerCodecConfigurer serverCodecConfigurer) { this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList); this.serverCodecConfigurer = serverCodecConfigurer; } /** * 限流异常处理器 * * @return */ @Bean @Order(Ordered.HIGHEST_PRECEDENCE) public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() { // Register the block exception handler for Spring Cloud Gateway. return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer); } /** * 限流过滤器 * * @return */ @Bean @Order(Ordered.HIGHEST_PRECEDENCE) public GlobalFilter sentinelGatewayFilter() { return new SentinelGatewayFilter(); } /** * Spring 容器初始化的时候执行该方法 */ @PostConstruct public void doInit() { // 加载网关限流规则 initGatewayRules(); } /** * 网关限流规则 */ private void initGatewayRules() { Set<GatewayFlowRule> rules = new HashSet<>(); /* resource：资源名称，可以是网关中的 route 名称或者用户自定义的 API 分组名称 count：限流阈值 intervalSec：统计时间窗口，单位是秒，默认是 1 秒 */ rules.add(new GatewayFlowRule("order-service") .setCount(3) // 限流阈值 .setIntervalSec(60)); // 统计时间窗口，单位是秒，默认是 1 秒 // 加载网关限流规则 GatewayRuleManager.loadRules(rules); } } 启动类GatewayServerSentinelApplication.java
package com.example; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; // 开启 EurekaClient 注解，目前版本如果配置了 Eureka 注册中心，默认会开启该注解 //@EnableEurekaClient @SpringBootApplication public class GatewayServerSentinelApplication { public static void main(String[] args) { SpringApplication.run(GatewayServerSentinelApplication.class, args); } } 访问多次访问：:9001/order/1 结果如下：
接口 BlockRequestHandler 的默认实现为 DefaultBlockRequestHandler，当触发限流时会返回默认的错误信息：Blocked by Sentinel: FlowException。我们可以通过 GatewayCallbackManager 定制异常提示信息。
自定义异常提示GatewayCallbackManager 的 setBlockHandler 注册函数用于实现自定义的逻辑，处理被限流的请求。
package com.example.config; import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule; import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager; import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter; import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler; import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager; import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler; import org.springframework.beans.factory.ObjectProvider; import org.springframework.cloud.gateway.filter.GlobalFilter; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.core.Ordered; import org.springframework.core.annotation.Order; import org.springframework.http.HttpStatus; import org.springframework.http.MediaType; import org.springframework.http.codec.ServerCodecConfigurer; import org.springframework.web.reactive.function.BodyInserters; import org.springframework.web.reactive.function.server.ServerResponse; import org.springframework.web.reactive.result.view.ViewResolver; import org.springframework.web.server.ServerWebExchange; import reactor.core.publisher.Mono; import javax.annotation.PostConstruct; import java.util.*; /** * 限流规则配置类 */ @Configuration public class GatewayConfiguration { private final List<ViewResolver> viewResolvers; private final ServerCodecConfigurer serverCodecConfigurer; /** * 构造器 * * @param viewResolversProvider * @param serverCodecConfigurer */ public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider, ServerCodecConfigurer serverCodecConfigurer) { this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList); this.serverCodecConfigurer = serverCodecConfigurer; } /** * 限流异常处理器 * * @return */ @Bean @Order(Ordered.HIGHEST_PRECEDENCE) public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() { // Register the block exception handler for Spring Cloud Gateway. return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer); } /** * 限流过滤器 * * @return */ @Bean @Order(Ordered.HIGHEST_PRECEDENCE) public GlobalFilter sentinelGatewayFilter() { return new SentinelGatewayFilter(); } /** * Spring 容器初始化的时候执行该方法 */ @PostConstruct public void doInit() { // 加载网关限流规则 initGatewayRules(); // 加载自定义限流异常处理器 initBlockHandler(); } /** * 网关限流规则 */ private void initGatewayRules() { Set<GatewayFlowRule> rules = new HashSet<>(); /* resource：资源名称，可以是网关中的 route 名称或者用户自定义的 API 分组名称 count：限流阈值 intervalSec：统计时间窗口，单位是秒，默认是 1 秒 */ rules.add(new GatewayFlowRule("order-service") .setCount(3) // 限流阈值 .setIntervalSec(60)); // 统计时间窗口，单位是秒，默认是 1 秒 // 加载网关限流规则 GatewayRuleManager.loadRules(rules); } /** * 自定义限流异常处理器 */ private void initBlockHandler() { BlockRequestHandler blockRequestHandler = new BlockRequestHandler() { @Override public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) { Map<String, String> result = new HashMap<>(); result.put("code", String.valueOf(HttpStatus.TOO_MANY_REQUESTS.value())); result.put("message", HttpStatus.TOO_MANY_REQUESTS.getReasonPhrase()); result.put("route", "order-service"); return ServerResponse.status(HttpStatus.TOO_MANY_REQUESTS) .contentType(MediaType.APPLICATION_JSON) .body(BodyInserters.fromValue(result)); } }; // 加载自定义限流异常处理器 GatewayCallbackManager.setBlockHandler(blockRequestHandler); } }「访问」
多次访问：:9001/order/1 结果如下：
「访问」
访问：:9001/product-service/product/1 「触发限流」
访问：:9001/order-service/order/index 「触发限流」
访问：:9001/order-service/order/1 「不会触发限流」
至此 Sentinel 服务哨兵知识点就讲解结束了。