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

• Controller中编写测试逻辑，添加@SentinelResource，并配置blockHandler和fallback

package com.wang.controller;import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.concurrent.TimeUnit;/*** @BelongsProject: SpringCloudAlibabaLearn* @BelongsPackage: com.wang.controllter* @Author: wang fei* @CreateTime: 2023-01-16  16:48* @Description: TODO* @Version: 1.0*/
@RestController
@RequestMapping("/order")
public class OrderController {@GetMapping("/pay")@SentinelResource(value = "pay",blockHandler = "flowBlockHandler")public String pay(){return "success";}@GetMapping("/flowThread")@SentinelResource(value = "flowThread",blockHandler = "flowBlockHandler")public String flowThread() throws InterruptedException {TimeUnit.SECONDS.sleep(5);return "success";}//自定义流控处理返回方法public String flowBlockHandler(BlockException e){return "流控成功 ,阻塞服务";}@GetMapping("/add")public String add(){return "下单成功";}@GetMapping("/get")public String get(){return "查询成功";}/*** 热点规则，必须使用@SentinelResource* @param id* @return* @throws InterruptedException*/@RequestMapping("/get/{id}")@SentinelResource(value = "getById",blockHandler = "HotBlockHandler")public String getById(@PathVariable("id") Integer id) throws InterruptedException {System.out.println("正常访问");return "正常访问";}public String HotBlockHandler(@PathVariable("id") Integer id,BlockException e) throws InterruptedException {return "热点异常处理";}
}

• 编写MyBlockExceptionHandler

package com.wang.exception;import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.BlockExceptionHandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.authority.AuthorityException;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowException;
import com.alibaba.csp.sentinel.slots.system.SystemBlockException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.wang.domain.Result;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** @author 飞*/
@Component
public class MyBlockExceptionHandler implements BlockExceptionHandler {Logger log= LoggerFactory.getLogger(this.getClass());@Overridepublic void handle(HttpServletRequest httpServletRequest, HttpServletResponse response, BlockException e) throws Exception {// getRule() 资源  规则的详细信息log.info("BlockExceptionHandler BlockException================"+e.getRule());Result r = null;if (e instanceof FlowException) {r = Result.error(100,"接口限流了");} else if (e instanceof DegradeException) {r = Result.error(101,"服务降级了");} else if (e instanceof ParamFlowException) {r = Result.error(102,"热点参数限流了");} else if (e instanceof SystemBlockException) {r = Result.error(103,"触发系统保护规则了");} else if (e instanceof AuthorityException) {r = Result.error(104,"授权规则不通过");}//返回json数据response.setStatus(500);response.setCharacterEncoding("utf-8");response.setContentType(MediaType.APPLICATION_JSON_VALUE);new ObjectMapper().writeValue(response.getWriter(), r);}
}

Result.java

package com.wang.domain;/*** @author 飞*/
public class Result<T> {private Integer code;private String msg;private T data;public Result(Integer code, String msg, T data) {this.code = code;this.msg = msg;this.data = data;}public Result(Integer code, String msg) {this.code = code;this.msg = msg;}public Integer getCode() {return code;}public void setCode(Integer code) {this.code = code;}public String getMsg() {return msg;}public void setMsg(String msg) {this.msg = msg;}public T getData() {return data;}public void setData(T data) {this.data = data;}public static Result error(Integer code, String msg){return new Result(code,msg);}
}

server:port: 8070
spring:application:name: order-sentinelcloud:sentinel:transport:dashboard: 127.0.0.1:8080web-context-unify: false  # 默认将调用链路收敛, 导致链路流控效果无效datasource:flow-rule:nacos:server-addr: 127.0.0.1:8848 # nacos地址username: nacospassword: nacosdataId: order-sentinel-flow-rulerule-type: flow

3.启动 Sentinel 控制台

 java ‐jar sentinel‐dashboard‐1.8.0.jar

• 用户可以通过如下参数进行配置：

• 为了方便快捷启动可以在桌面创建.bat文件

java ‐Dserver.port=8858 ‐Dsentinel.dashboard.auth.username=xushu Dsentinel.dashboard.auth.password=123456 ‐jar D:\s
erver\sentinel‐dashboard‐1.8.0.jar
pause

Sentinel 会在客户端首次调用的时候进行初始化，开始向控制台发送心跳包，所以要确保客户端有访问量；

 4. Spring Cloud Alibaba整合Sentine

    2.2步骤

5.Sentinel控制台规则配置详解

• 流量控制（flow control），其原理是监控应用流量的 QPS 或并发线程数等指标，当达到指定的阈值时对流量进行控制，

<!--        openfeig 远程调用--><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-openfeign</artifactId></dependency><!--sentinel依赖--><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-sentinel</artifactId></dependency>

feign:sentinel:# openfeign整合sentinelenabled: true

package com.wang.feign;import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;@FeignClient(value="stock-nacos",path = "/stock",fallback = StockFeignServiceFallback.class)
public interface StockFeignService {@RequestMapping("/reduct")public String reduct2();
}

[{"resource": "/order/pay","controlBehavior": 0,"count": 3.0,"grade": 1,
"limitApp": "default","strategy": 0}]

package com.wang.controller;import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.concurrent.TimeUnit;/*** @BelongsProject: SpringCloudAlibabaLearn* @BelongsPackage: com.wang.controllter* @Author: wang fei* @CreateTime: 2023-01-16  16:48* @Description: TODO* @Version: 1.0*/
@RestController
@RequestMapping("/order")
public class OrderController {@GetMapping("/pay")
//    @SentinelResource(value = "pay",blockHandler = "flowBlockHandler")public String pay(){return "success";}@GetMapping("/flowThread")@SentinelResource(value = "flowThread",blockHandler = "flowBlockHandler")public String flowThread() throws InterruptedException {TimeUnit.SECONDS.sleep(5);return "success";}//自定义流控处理返回方法public String flowBlockHandler(BlockException e){return "流控成功 ,阻塞服务";}@GetMapping("/add")public String add(){return "下单成功";}@GetMapping("/get")public String get(){return "查询成功";}/*** 热点规则，必须使用@SentinelResource* @param id* @return* @throws InterruptedException*/@RequestMapping("/get/{id}")@SentinelResource(value = "getById",blockHandler = "HotBlockHandler")public String getById(@PathVariable("id") Integer id) throws InterruptedException {System.out.println("正常访问");return "正常访问";}public String HotBlockHandler(@PathVariable("id") Integer id,BlockException e) throws InterruptedException {return "热点异常处理";}
}

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