Sentinel 官方网站

sentinel-dashboard-1.8.7.jar包下载地址

在window通过命令行启动（java -Dserver.port=8080 -Dproject.name=sentinel-dashboard -jar sentinel-dashboard-1.8.7.jar），可以通过 -Dserver.port修改控制台的端口

使用的版本最好都一致

注意：如果项目不是springcloud，不可以在yml配置dashboard的地址，配置也都是无效的。如果需要和dashboard整合有以下几种方法

方法一：启动参数配置项官网

-Dcsp.sentinel.dashboard.server=192.168.11.47:8858 #dashboard的访问路径

-Dcsp.sentinel.api.port=8869 #客户端监控 API 的端口（默认是 8719）

-Dproject.name=sentinel-name #指定应用的名称

-Dcsp.sentinel.heartbeat.client.ip=192.168.11.50 #客户端指定心跳包中本机的 IP

jar包启动的方式

java -Dproject.name=sentinel-name -Dcsp.sentinel.heartbeat.client.ip=192.168.11.50 -Dcsp.sentinel.api.port=8869 -Dcsp.sentinel.dashboard.server=192.168.11.47:8858 -jar sentinel-demo.jar

在代码中设置的方式

System.setProperty("project.name", "sentinel-name");
System.setProperty("csp.sentinel.heartbeat.client.ip", "192.168.11.50");
System.setProperty("csp.sentinel.api.port", "8869");
System.setProperty("csp.sentinel.dashboard.server", "192.168.11.47:8858");

idea配置的方式

pom的配置有两种方式，spring-cloud-starter-alibaba-sentinel包含sentinel全部的core和annotation等之类的依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.6.11</version><relativePath/> <!-- lookup parent from repository --></parent><modelVersion>4.0.0</modelVersion><artifactId>sentinel-demo</artifactId><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.26</version></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-sentinel</artifactId><version>2021.0.4.0</version></dependency></dependencies>
</project>

pom.xml：简约包

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.6.11</version><relativePath/> <!-- lookup parent from repository --></parent><modelVersion>4.0.0</modelVersion><artifactId>sentinel-demo</artifactId><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--sentinel核心库--><dependency><groupId>com.alibaba.csp</groupId><artifactId>sentinel-core</artifactId><version>1.8.5</version></dependency><!--如果要使用注解@SentinelResource--><dependency><groupId>com.alibaba.csp</groupId><artifactId>sentinel-annotation-aspectj</artifactId><version>1.8.5</version></dependency><!--客户端接入控制台--><dependency><groupId>com.alibaba.csp</groupId><artifactId>sentinel-transport-simple-http</artifactId><version>1.8.5</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.26</version></dependency></dependencies>
</project>

使用编写代码的方式实现(流控降级)熔断，不使用dashboard，这是流控规则，保存在代码中

package com.test.order.controller;import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.Tracer;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.RuleConstant;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;/*** @Description:* @Author: xu* @Data: 2024-2024/3/29-16* @Version: V1.0*/
@RestController
@RequestMapping("/order")
public class OrderController {private final static String resourceName = "flow";private static Logger log = LoggerFactory.getLogger(OrderController.class);@RequestMapping("/flow")public String flow() {System.out.println("aaaaaaaaaaaaaaaaa");Entry entry = null;//务必保证 finally 会被执行try {// 资源名可使用任意有业务语义的字符串开启资源的保护entry = SphU.entry(resourceName);//被保护的业务逻辑method//do something...} catch (BlockException ex) {//资源访问阻止，被限流或被降级//Sentinel定义异常 流控规则，降级规则，热点参数规则。。服务降级(降级规则)//进行相应的处理操作log.info("block！！！");return "被流控了";} catch (Exception ex) {//若需要配置降级规则，需要通过这种方式记录业务异常RuntimeExceptionmock feign:fallbackTracer.traceEntry(ex, entry);} finally {//务必保证 exit，务必保证每个 entry 与 exit 配对if (entry != null) {entry.exit();}}return "flow";}@PostConstructprivate void initFlowQpsRule() {List<FlowRule> rules = new ArrayList<>();FlowRule rule = new FlowRule(resourceName);// set limit qps to 20rule.setCount(2);rule.setGrade(RuleConstant.FLOW_GRADE_QPS);rule.setLimitApp("default");rules.add(rule);FlowRuleManager.loadRules(rules);}}

可使用注解的方式简介编写@SentinelResource，使用@SentinelResource注意事项可以查看注解埋点官网

package com.test.order.controller;import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.Tracer;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.RuleConstant;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;/*** @Description:* @Author: xu* @Data: 2024-2024/3/29-16* @Version: V1.0*/
@RestController
@RequestMapping("/order")
public class OrderController {private final static String resourceName = "flow";private static Logger log = LoggerFactory.getLogger(OrderController.class);//blockHandler / blockHandlerClass: blockHandler 对应处理 BlockException 的函数名称，可选项。// blockHandler 函数访问范围需要是 public，返回类型需要与原方法相匹配，参数类型需要和原方法相匹配并且最后加一个额外的参数，类型为 BlockException。// blockHandler 函数默认需要和原方法在同一个类中。若希望使用其他类的函数，则可以指定 blockHandlerClass 为对应的类的 Class 对象，注意对应的函数必需为 static 函数，否则无法解析//fallback / fallbackClass：fallback 函数名称，可选项，用于在抛出异常的时候提供 fallback 处理逻辑。// fallback 函数可以针对所有类型的异常//blockHandler的优先级比fallback高，官网中都有讲解 https://github.com/alibaba/Sentinel/wiki/%E6%B3%A8%E8%A7%A3%E6%94%AF%E6%8C%81@RequestMapping("/flow")@SentinelResource(value = resourceName, blockHandler = "exceptionHandler",fallback = "helloFallback")public String flow() {System.out.println("aaaaaaaaaaaaaaaaa");//被保护的业务逻辑method//do something...return "flow";}public String exceptionHandler(BlockException ex) {// Do some log here.ex.printStackTrace();return "被流控了";}// Fallback 函数，函数签名与原函数一致或加一个 Throwable 类型的参数.public String helloFallback(long s) {return String.format("Halooooo %d", s);}@PostConstructprivate void initFlowQpsRule() {List<FlowRule> rules = new ArrayList<>();FlowRule rule = new FlowRule(resourceName);// set limit qps to 20rule.setCount(2);rule.setGrade(RuleConstant.FLOW_GRADE_QPS);rule.setLimitApp("default");rules.add(rule);FlowRuleManager.loadRules(rules);}}

这是降级规则，保存在代码中

@PostConstruct
private void initDegradeRule() {List<DegradeRule> rules = new ArrayList<>();DegradeRule rule = new DegradeRule();rule.setResource(resourceName);// set threshold RT, 10 msrule.setCount(10);rule.setGrade(RuleConstant.DEGRADE_GRADE_RT);rule.setTimeWindow(10);rules.add(rule);DegradeRuleManager.loadRules(rules);
}@RequestMapping("/degrade")@SentinelResource(value = resourceName, entryType = EntryType.IN,  blockHandler = "exceptionHandler2", fallback = "helloFallback2")public String degrade() {throw new RuntimeException("异常");}

其他的规则都是类似的原理可以查看官网使用

整合后可以在界面查看

如果项目是springcloud项目，可以直接在yml配置

server:port: 8079
spring:application:name: order-sentinelcloud:sentinel:transport:dashboard: 192.168.11.47:8858#注意：yml配置client-ip 是本地ip才行client-ip: 192.168.11.50port: 8719

pom.xml依赖

<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>