代碼

import cn.hutool.core.util.StrUtil;
import com.alibaba.csp.sentinel.datasource.ReadableDataSource;
import com.alibaba.csp.sentinel.datasource.zookeeper.ZookeeperDataSource;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRule;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.zookeeper.ZookeeperProperties;
import org.springframework.stereotype.Component;import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.util.List;@Component
public class ZkDataSourceConfig {@Value("${spring.application.name}")private String appname;@Value("${spring.profiles.active}")private String profile;@Resourceprivate ZookeeperProperties zookeeperProperties;@PostConstructpublic void init() {loadRules(zookeeperProperties.getConnectString());}private void loadRules(String remoteAddress) {// 規則會持久化到zk的/groupId/flowDataId節點// groupId和和flowDataId可以用/開頭也可以不用// 建議不用以/開頭，目的是為了如果從Zookeeper切換到Nacos的話，只需要改數據源類名就可以String groupId = StrUtil.format("sentinel/{}:{}", appname, profile);ReadableDataSource<String, List<FlowRule>> flowRuleDataSource = new ZookeeperDataSource<>(remoteAddress, groupId, "FlowRule",// source 就是從 zookeeper 中讀出來的字符串source -> JSON.parseObject(source, new TypeReference<List<FlowRule>>() {}));//限流FlowRuleManager.register2Property(flowRuleDataSource.getProperty());ReadableDataSource<String, List<DegradeRule>> degradeRuleDataSource = new ZookeeperDataSource<>(remoteAddress, groupId, "DegradeRule",// source 就是從 zookeeper 中讀出來的字符串source -> JSON.parseObject(source, new TypeReference<List<DegradeRule>>() {}));//降級DegradeRuleManager.register2Property(degradeRuleDataSource.getProperty());}
}

ZK配置參考

/sentinel/應用名:環境=FlowRule=[{"resource": "資源1", "limitApp": "default", "grade": 1, "count": 40.0, "strategy": 0, "controlBehavior": 2, "maxQueueingTimeMs": 100000 }, {"resource": "資源2", "limitApp": "default", "grade": 1, "count": 40.0, "strategy": 0, "controlBehavior": 2, "maxQueueingTimeMs": 100000 }, {"resource": "資源3", "limitApp": "default", "grade": 1, "count": 10.0, "strategy": 0, "controlBehavior": 2, "maxQueueingTimeMs": 100000 } ]

使用

public class demo {public static void main(String[] args) {// 定義規則initFlowRules();//用SphU.entry()的形式定義資源while (true) {try (Entry entry = SphU.entry("myResource")) {//與規則定義中的rule.setResource("myResource")一致// 被保護的業務邏輯...System.out.println("業務資源訪問成功！");} catch (BlockException ex) {// 處理被流控的邏輯：限流或降級...System.out.println("資源訪問失敗！！！");} finally {if (entry != null) {entry.exit();//必須退出資源調用}}}//用SphO.entry()的形式定義資源while (true) {if(SphO.entry("myResource")){//與規則定義中的rule.setResource("myResource")一致try{// 被保護的業務邏輯...System.out.println("業務資源訪問成功！");} catch (BlockException ex) {// 處理被流控的邏輯：限流或降級...System.out.println("資源訪問失敗！！！");}finally{SphO.exit();//必須退出資源調用}}}//上面兩種方式對代碼侵入性很高，可用注解的方式定義資源while(true){getUserById("111");}}//文章開始通過zk加載配置，此處通過代碼定義規則	//定義規則 private static void initFlowRules(){List<FlowRule> rules = new ArrayList<>();// 存儲規則 FlowRuleFlowRule rule = new FlowRule();rule.setResource("myResource");	// 指定限流規則作用于哪個資源上，資源名為字符串，可為任意有標識意義的方法名/接口名/其他字符串，此處資源名為"myResource"rule.setGrade(RuleConstant.FLOW_GRADE_QPS);	// 限流類型為QPS模式：限制QPSrule.setCount(10);	   // QPS不得超出10rule.setLimitApp("default");	// 針對的調用來源，default代表不區分來源rules.add(rule);FlowRuleManager.loadRules(rules);// 加載規則}//定義"myResource"資源，并設置違背sentinel流控規則時的處理方法handlerException()@SentinelResource(value="myResource",blockHandler="handlerException")public User getUserById(String id){return new User("數據庫用戶")；}//注意：此處理方法的參數必須和定義資源的方法getUserById參數一致（）同時加上【BlockException exception】參數public User handlerException(String id,BlockException exception){return new User("流控用戶");}
}

Entry entry = null;
try {entry = SphU.entry("myResource"); //此處說明資源// 被保護的業務邏輯...
} catch (BlockException e1) {// 資源訪問阻止，被限流或被降級,進行相應的處理操作...
} finally {if (entry != null) {entry.exit();}
}