客戶端請求
    │
    ▼
┌─────────────────────────────┐
│  Gateway (9528)              │
│  ┌─────────────────────────┐ │
│  │ SentinelGatewayFilter    │ │ ← 在這里攔截！超閾值直接拒絕
│  │ (網(wǎng)關(guān)層限流 QPS=2)       │ │
│  └─────────┬───────────────┘ │
│            │ 通過限流         │
└────────────┼────────────────┘
             ▼
┌─────────────────────────────┐
│  Provider (9001)             │
│  ┌─────────────────────────┐ │
│  │ @SentinelResource        │ │ ← 服務(wù)層精細化限流
│  └─────────────────────────┘ │
└─────────────────────────────┘

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<!-- Sentinel 適配 Gateway 的橋接包 -->
<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
</dependency>

server:
  port: 9528
spring:
  application:
    name: cloudalibaba-sentinel-gateway
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
    gateway:
      routes:
        - id: pay_routh1
          uri: http://localhost:9001        # 直接轉(zhuǎn)發(fā)到 Provider
          predicates:
            - Path=/pay/**
    sentinel:
      log:
        dir: D:/yangnan/Documents/SpringCloud/sentinel-log

// clooudalibaba-sentinel-gateway9528/.../config/GatewayConfiguration.java
@Configuration
public class GatewayConfiguration {
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;
    public GatewayConfiguration(
            ObjectProvider<List<ViewResolver>> viewResolversProvider,
            ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }
    // ① 注冊 Sentinel 異常處理器（最高優(yōu)先級）
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(
            viewResolvers, serverCodecConfigurer);
    }
    // ② 注冊 Sentinel 全局過濾器（Order=-1，低于上方的處理器，但高于其他過濾器）
    @Bean
    @Order(-1)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }
    // ③ 應(yīng)用啟動后初始化規(guī)則
    @PostConstruct
    public void doInit() {
        initBlockHandler();
    }
    private void initBlockHandler() {
        // 網(wǎng)關(guān)流控規(guī)則：對路由 pay_routh1 限制每秒最多 2 個請求
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(new GatewayFlowRule("pay_routh1")
            .setCount(2)           // QPS 閾值
            .setIntervalSec(1));   // 統(tǒng)計間隔 1 秒
        GatewayRuleManager.loadRules(rules);
        // 自定義限流響應(yīng)（返回 JSON 而不是默認 HTML）
        BlockRequestHandler handler = (exchange, t) -> {
            Map<String, String> map = new HashMap<>();
            map.put("errorCode",
                HttpStatus.TOO_MANY_REQUESTS.getReasonPhrase());
            map.put("errorMessage",
                "請求太過頻繁，系統(tǒng)忙不過來，觸發(fā)限流(sentinel+gateway整合Case)");
            return ServerResponse.status(HttpStatus.TOO_MANY_REQUESTS)
                .contentType(MediaType.APPLICATION_JSON)
                .body(BodyInserters.fromValue(map));
        };
        GatewayCallbackManager.setBlockHandler(handler);
    }
}

{
    "errorCode": "Too Many Requests",
    "errorMessage": "請求太過頻繁，系統(tǒng)忙不過來，觸發(fā)限流(sentinel+gateway整合Case)"
}

請求到達 Gateway
    │
    ▼
SentinelGatewayFilter.doFilter()
    │
    ├→ 提取 routeId（如 "pay_routh1"）
    ├→ 匹配 GatewayFlowRule（QPS=2）
    ├→ 判斷是否超閾值
    │
    ├→ 未超：chain.filter() → 轉(zhuǎn)發(fā)到 Provider ?
    └→ 超了：throw BlockException → BlockRequestHandler → 返回 JSON ?