Sentinel热点参数限流完整示例实现

Sentinel热点参数限流完整示例实现

1. 添加Maven依赖 (pom.xml)

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
    <version>2.2.7.RELEASE</version>
</dependency>
<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-datasource-nacos</artifactId>
    <version>1.8.6</version>
</dependency>

2. 配置文件 (application.yml)

spring:
  cloud:
    sentinel:
      transport:
        dashboard: localhost:8080  # Sentinel控制台地址
        port: 8719
      datasource:
        ds1:
          nacos:
            server-addr: localhost:8848
            dataId: ${spring.application.name}-sentinel
            groupId: DEFAULT_GROUP
            rule-type: param-flow

# 自定义限流规则配置
sentinel:
  hot-param:
    activity-qps: 100  # 活动ID参数限流阈值

3. 热点参数限流规则配置类

创建 config/SentinelConfig.java:

import com.alibaba.csp.sentinel.slots.block.RuleConstant;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowItem;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowRuleManager;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;

import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;

@Configuration
public class SentinelConfig {

    @Value("${sentinel.hot-param.activity-qps:100}")
    private int activityQps;

    @PostConstruct
    public void initParamFlowRules() {
        List<ParamFlowRule> rules = new ArrayList<>();

        // 拼团活动热点参数限流规则
        ParamFlowRule activityRule = new ParamFlowRule();
        activityRule.setResource("createGroupActivity"); // 资源名称
        activityRule.setGrade(RuleConstant.FLOW_GRADE_QPS); // 限流阈值类型(QPS)
        activityRule.setCount(activityQps); // 限流阈值
        activityRule.setParamIdx(1); // 参数索引，0表示第一个参数，1表示第二个参数

        // 例外项配置 (可选)
        List<ParamFlowItem> paramItems = new ArrayList<>();
        // 对特定活动ID设置不同的阈值
        paramItems.add(new ParamFlowItem().setObject(String.valueOf(1001)).setCount(200).setClassType(String.class.getName()));
        activityRule.setParamFlowItemList(paramItems);

        rules.add(activityRule);
        ParamFlowRuleManager.loadRules(rules);
    }
}

4. 服务中使用热点参数限流

创建 GroupActivityServiceImpl.java:

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

@Service
@Slf4j
public class GroupActivityServiceImpl implements GroupActivityService {

    /**
     * 创建拼团活动接口，对活动ID进行热点参数限流
     * @param userId 用户ID
     * @param activityId 活动ID (热点参数)
     * @param dto 创建活动DTO
     * @return 活动创建结果
     */
    @Override
    @SentinelResource(
        value = "createGroupActivity", // 资源名称，需与规则中配置一致
        blockHandler = "createGroupActivityBlockHandler", // 限流降级处理方法
        fallback = "createGroupActivityFallback" // 异常降级处理方法
    )
    public String createGroupActivity(Long userId, String activityId, GroupActivityCreateDTO dto) {
        // 业务逻辑实现
        log.info("用户{}创建拼团活动: {}", userId, activityId);
        return "活动创建成功: " + activityId;
    }

    /**
     * 热点参数限流降级处理
     */
    public String createGroupActivityBlockHandler(Long userId, String activityId, GroupActivityCreateDTO dto, BlockException e) {
        log.warn("拼团活动创建限流, userId:{}, activityId:{}", userId, activityId, e);
        return "当前活动太火爆，请稍后再试!";
    }

    /**
     * 异常降级处理
     */
    public String createGroupActivityFallback(Long userId, String activityId, GroupActivityCreateDTO dto, Throwable e) {
        log.error("拼团活动创建异常, userId:{}, activityId:{}", userId, activityId, e);
        return "活动创建失败，请稍后重试!";
    }
}

5. Nacos动态规则配置

在Nacos控制台添加配置，Data ID: app-sentinel, Group: DEFAULT_GROUP:

[
  {
    "resource": "createGroupActivity",
    "grade": 1,
    "count": 100,
    "paramIdx": 1,
    "paramFlowItemList": [
      {
        "object": "1001",
        "classType": "java.lang.String",
        "count": 200
      }
    ],
    "clusterMode": false
  }
]

实现说明

1. 依赖说明：引入了Sentinel核心包和Nacos数据源支持，实现规则动态推送
2. 参数索引 ：paramIdx: 1表示对方法的第二个参数(activityId)进行限流
3. 例外项配置：对特定活动ID(如1001)设置更高的阈值
4. 降级策略：分别实现了限流降级和异常降级两种处理逻辑
5. 动态配置：支持通过Nacos控制台实时调整限流规则，无需重启服务

使用时需确保Sentinel控制台和Nacos服务已启动，具体部署可参考项目中docs/dev-ops目录下的部署文档。