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: 8719datasource:ds1:nacos:server-addr: localhost:8848dataId: ${spring.application.name}-sentinelgroupId: DEFAULT_GROUPrule-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;@PostConstructpublic 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}
]