<!-- 3.引入sentinel对gateway的支持 -->
<dependency>
  <groupId>com.alibaba.csp</groupId>
  <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
</dependency>

import java.util.Collections;
import java.util.List;

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 com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;

@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;
    }

    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        // Register the block exception handler for Spring Cloud Gateway.
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }
}

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.context.annotation.Configuration;

import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager;

@Configuration
public class SentinelApplicationRunner implements ApplicationRunner {

    @Override
    public void run(ApplicationArguments args) throws Exception {
        initGatewayRules();
    }
    
    /**
     * 配置Gateway限流规则
     */
    public void initGatewayRules() {
        GatewayFlowRule gatewayFlowRule = new GatewayFlowRule();
        gatewayFlowRule.setResource("qfx-product")  // 路由ID
                    .setCount(1)                // 限流阈值
                    .setIntervalSec(1); // 统计时间窗口,单位是秒,默认是1秒
        
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(gatewayFlowRule);
        
        GatewayRuleManager.loadRules(rules);
    }
}

import java.nio.charset.StandardCharsets;
import java.util.List;

import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.reactive.result.view.ViewResolver;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebExceptionHandler;

import reactor.core.publisher.Mono;

public class MySentinelGatewayBlockExceptionHandler implements WebExceptionHandler {
    public MySentinelGatewayBlockExceptionHandler(List<ViewResolver> viewResolvers, ServerCodecConfigurer serverCodecConfigurer) {
        
    }

    @Override
    public Mono<Void> handle(ServerWebExchange exchange, Throwable ex) {
        ServerHttpResponse serverHttpResponse = exchange.getResponse();
        serverHttpResponse.getHeaders().add("Content-Type", "application/json;charset=UTF-8");
        byte[] datas = "{\"code\":403,\"msg\":\"API接口被限流\"}".getBytes(StandardCharsets.UTF_8);
        DataBuffer buffer = serverHttpResponse.bufferFactory().wrap(datas);
        return serverHttpResponse.writeWith(Mono.just(buffer));
    }
}

@Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public MySentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        // 自定义的限流异常处理类.
        return new MySentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

import java.util.Collections;
import java.util.List;

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 com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;
import com.qfx.common.handler.MySentinelGatewayBlockExceptionHandler;

@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;
    }

//    @Bean
//    @Order(Ordered.HIGHEST_PRECEDENCE)
//    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
//        // Register the block exception handler for Spring Cloud Gateway.
//        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
//    }
    
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public MySentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        // 自定义的限流异常处理类.
        return new MySentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }
}