0.9.0.RELEASE版本的spring cloud alibaba sentinel+gateway網關實例

　　sentinel除了讓服務提供方、消費方用之外，網關也能用它來限流。我們基於上次整的網關（參見0.9.0.RELEASE版本的spring cloud alibaba nacos+gateway網關實例）來看下怎么弄。只需動其中的兩板斧：

　　1、pom引入sentinel適配器：

        <dependency>
            <groupId>com.alibaba.csp</groupId>
            <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
            <version>1.6.0</version>
        </dependency>

　　2、新增一個配置類：

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;

@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;
    }

    /**
     * 配置SentinelGatewayBlockExceptionHandler，限流后異常處理
     *
     * @return
     */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    @Bean
    @Order(-1)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }

    @PostConstruct
    public void doInit() {
        initGatewayRules();
    }

    /**
     * 配置限流規則
     */
    private void initGatewayRules() {
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(new GatewayFlowRule("lxytrans-consumer")
                .setCount(4) // 限流閾值
                .setIntervalSec(1) // 統計時間窗口，單位是秒，默認是 1 秒
        );
        rules.add(new GatewayFlowRule("lxytrans-provider")
                .setCount(3)
                .setIntervalSec(1)
        );
        GatewayRuleManager.loadRules(rules);
    }
}

　　打完收功。把網關重新跑起來，我們依然基於之前的服務提供方和消費方測試，消費方並發5個限1個，提供方並發5個限2個：