server:
  port: 8091
  tomcat:
    max-threads: 2     #最大线程数
    max-connections: 10  #最大连接数
    accept-count: 10     #最大线程等待数
spring:
  application:
    name: service-order
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848

进入bin目录,修改jmeter.properties文件中的语言支持为language=zh_CN，然后点击jmeter.bat，启动软件。

1.熔断关闭状态（Closed）：服务没有故障时，熔断器所处的状态，对调用方的调用不做任何限制
2.熔断开启状态（Open）：后续对该服务接口的调用不再经过网络，直接执行本地的fallback方法
3.半熔断状态（Half-Open）：
4.尝试恢复服务调用，允许有限的流量调用该服务，并监控调用成功率。如果成功率达到预期，则说明服务已恢复，进入熔断关闭状态；如果成功率仍旧很低，则重新进入熔断关闭状态。

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

server:
  port: 8091
  tomcat:
    max-threads: 2     #最大线程数
    max-connections: 10  #最大连接数
    accept-count: 10     #最大线程等待数
spring:
  application:
    name: service-order
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
    sentinel:
      transport:
        port: 9999 #跟控制台交流的端口,随意指定一个未使用的端口即可
        dashboard: localhost:8080 # 指定控制台服务的地址

# 直接使用jar命令启动项目(控制台本身是一个SpringBoot项目)
java -Dserver.port=8080 -Dcsp.sentinel.dashboard.server=localhost:8080 -Dproject.name=sentinel-dashboard -jar sentinel-dashboard-1.8.4.jar
#参考1
java -jar sentinel-dashboard-1.8.4.jar --server.port=8080
#参考2
java -Dserver.port=8080 -Dcsp.sentinel.dashboard.server=localhost:8080 -Dproject.name=sentinel-dashboard -jar sentinel-dashboard-1.8.4.jar

@RequestMapping("/message1")
public String message1(){
    System.out.println("message1");
    return "message1";
}
@RequestMapping("/message2")
public String message2(){
    System.out.println("message2");
    return "message2";
}

package com.zjzaki.shoporder.service;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import org.springframework.stereotype.Service;
import java.util.HashMap;
import java.util.Map;
@Service
public class OrderServiceImpl2 {
    @SentinelResource(value = "message", blockHandler = "failBlockHandler")
    public Map message() {
        Map map = new HashMap();
        map.put("code","200");
        map.put("msg","正常响应成功");
      return map;
    }
    public Map failBlockHandler(BlockException be) {
        Map map = new HashMap();
        map.put("code","-1");
        map.put("msg","接口被限流了...");
        return map;
    }
}

@Autowired
    private OrderServiceImpl2 orderService;
    //        主要讲解 sentinel 中的 链路流控模式
    @RequestMapping("/message3")
    public Map message3() {
        return orderService.message();
    }
    
    @RequestMapping("/message4")
    public Map message4() {
        return orderService.message();
    }

server:
  port: 8091
  tomcat:
    max-threads: 2     #最大线程数
    max-connections: 10  #最大连接数
    accept-count: 10     #最大线程等待数
spring:
  application:
    name: service-order
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
    sentinel:
      transport:
        port: 9999 #跟控制台交流的端口,随意指定一个未使用的端口即可
        dashboard: localhost:8080 # 指定控制台服务的地址
      web-context-unify: false

/**
* sentinel 中的熔断降级，平均响应时间，预测结果：平均时间大于0.22s，那么出现降级处理结果
* @return
*/
@RequestMapping("/message5")
public String message5() {
    try {
        TimeUnit.MILLISECONDS.sleep(220);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    return "message5";
}

int i = 0;
//sentinel熔断降级：异常比例
@RequestMapping("/message6")
public String message6() {
    i++;
    //异常比例为0.333
    if (i % 3 == 0){
        throw new RuntimeException();
    }
    return "message6";
}

@RequestMapping("/order/message3")
@SentinelResource("message3")//注意这里必须使用这个注解标识,热点规则不生效
public String message3(String name, Integer age) {
  return name + age;
}

package com.zjzaki.shoporder.config;
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.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;
import com.alibaba.fastjson.JSON;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.stereotype.Component;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
//异常处理页面
@Component
public class ExceptionHandlerPage implements BlockExceptionHandler {
    @Override
    public void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception {
        response.setContentType("application/json;charset=utf-8");
        ResponseData data = null;
        if (e instanceof FlowException) {
            data = new ResponseData(-1, "接口被限流了...");
        } else if (e instanceof DegradeException) {
            data = new ResponseData(-2, "接口被降级了...");
        }
        response.getWriter().write(JSON.toJSONString(data));
    }
}
@Data
@AllArgsConstructor//全参构造
@NoArgsConstructor//无参构造
class ResponseData {
    private int code;
    private String message;
}

@Service
public class OrderMessageImpl {
    @SentinelResource("message")
    public String message(){
        return "message";
    }
}

package com.zjzaki.config;
import com.alibaba.csp.sentinel.command.handler.ModifyParamFlowRulesCommandHandler;
import com.alibaba.csp.sentinel.datasource.*;
import com.alibaba.csp.sentinel.init.InitFunc;
import com.alibaba.csp.sentinel.slots.block.authority.AuthorityRule;
import com.alibaba.csp.sentinel.slots.block.authority.AuthorityRuleManager;
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.csp.sentinel.slots.block.flow.param.ParamFlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowRuleManager;
import com.alibaba.csp.sentinel.slots.system.SystemRule;
import com.alibaba.csp.sentinel.slots.system.SystemRuleManager;
import com.alibaba.csp.sentinel.transport.util.WritableDataSourceRegistry;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import org.springframework.beans.factory.annotation.Value;
import java.io.File;
import java.io.IOException;
import java.util.List;
public class FilePersistence implements InitFunc {
    @Override
    public void init() throws Exception {
        String ruleDir = System.getProperty("user.home") + "/sentinel-rules/shopex";
        String flowRulePath = ruleDir + "/flow-rule.json";
        String degradeRulePath = ruleDir + "/degrade-rule.json";
        String systemRulePath = ruleDir + "/system-rule.json";
        String authorityRulePath = ruleDir + "/authority-rule.json";
        String paramFlowRulePath = ruleDir + "/param-flow-rule.json";
        this.mkdirIfNotExits(ruleDir);
        this.createFileIfNotExits(flowRulePath);
        this.createFileIfNotExits(degradeRulePath);
        this.createFileIfNotExits(systemRulePath);
        this.createFileIfNotExits(authorityRulePath);
        this.createFileIfNotExits(paramFlowRulePath);
        // 流控规则
        ReadableDataSource<String, List<FlowRule>> flowRuleRDS = new FileRefreshableDataSource<>(
                flowRulePath,
                flowRuleListParser
        );
        FlowRuleManager.register2Property(flowRuleRDS.getProperty());
        WritableDataSource<List<FlowRule>> flowRuleWDS = new FileWritableDataSource<>(
                flowRulePath,
                this::encodeJson
        );
        WritableDataSourceRegistry.registerFlowDataSource(flowRuleWDS);
        // 降级规则
        ReadableDataSource<String, List<DegradeRule>> degradeRuleRDS = new FileRefreshableDataSource<>(
                degradeRulePath,
                degradeRuleListParser
        );
        DegradeRuleManager.register2Property(degradeRuleRDS.getProperty());
        WritableDataSource<List<DegradeRule>> degradeRuleWDS = new FileWritableDataSource<>(
                degradeRulePath,
                this::encodeJson
        );
        WritableDataSourceRegistry.registerDegradeDataSource(degradeRuleWDS);
        // 系统规则
        ReadableDataSource<String, List<SystemRule>> systemRuleRDS = new FileRefreshableDataSource<>(
                systemRulePath,
                systemRuleListParser
        );
        SystemRuleManager.register2Property(systemRuleRDS.getProperty());
        WritableDataSource<List<SystemRule>> systemRuleWDS = new FileWritableDataSource<>(
                systemRulePath,
                this::encodeJson
        );
        WritableDataSourceRegistry.registerSystemDataSource(systemRuleWDS);
        // 授权规则
        ReadableDataSource<String, List<AuthorityRule>> authorityRuleRDS = new FileRefreshableDataSource<>(
                authorityRulePath,
                authorityRuleListParser
        );
        AuthorityRuleManager.register2Property(authorityRuleRDS.getProperty());
        WritableDataSource<List<AuthorityRule>> authorityRuleWDS = new FileWritableDataSource<>(
                authorityRulePath,
                this::encodeJson
        );
        WritableDataSourceRegistry.registerAuthorityDataSource(authorityRuleWDS);
        // 热点参数规则
        ReadableDataSource<String, List<ParamFlowRule>> paramFlowRuleRDS = new FileRefreshableDataSource<>(
                paramFlowRulePath,
                paramFlowRuleListParser
        );
        ParamFlowRuleManager.register2Property(paramFlowRuleRDS.getProperty());
        WritableDataSource<List<ParamFlowRule>> paramFlowRuleWDS = new FileWritableDataSource<>(
                paramFlowRulePath,
                this::encodeJson
        );
        ModifyParamFlowRulesCommandHandler.setWritableDataSource(paramFlowRuleWDS);
    }
    private Converter<String, List<FlowRule>> flowRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<FlowRule>>() {
            }
    );
    private Converter<String, List<DegradeRule>> degradeRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<DegradeRule>>() {
            }
    );
    private Converter<String, List<SystemRule>> systemRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<SystemRule>>() {
            }
    );
    private Converter<String, List<AuthorityRule>> authorityRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<AuthorityRule>>() {
            }
    );
    private Converter<String, List<ParamFlowRule>> paramFlowRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<ParamFlowRule>>() {
            }
    );
    private void mkdirIfNotExits(String filePath) throws IOException {
        File file = new File(filePath);
        if (!file.exists()) {
            file.mkdirs();
        }
    }
    private void createFileIfNotExits(String filePath) throws IOException {
        File file = new File(filePath);
        if (!file.exists()) {
            file.createNewFile();
        }
    }
    private <T> String encodeJson(T t) {
        return JSON.toJSONString(t);
    }
}

com.alibaba.csp.sentinel.init.InitFunc

com.zking.config.FilePersistence

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

# 开启feign对sentinel的支持
feign:
  sentinel:
    enabled: true

package com.zking.service;
import com.zking.domain.Product;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
//容错类要求必须实现被容错的接口,并为每个方法实现容错方案
@Component
@Slf4j
public class ProductServiceFallBack implements ProductService {
    @Override
    public Product findByPid(Integer pid) {
        Product product = new Product();
        product.setPid(-1);
        return product;
    }
}

//@FeignClient("service-product")//声明调用的提供者的name
//value用于指定调用nacos下哪个微服务
//fallback用于指定容错类
@FeignClient(value = "service-product", fallback = ProductServiceFallBack.class)
public interface ProductService {
    //指定调用提供者的哪个方法
    //@FeignClient+@GetMapping 就是一个完整的请求路径
    //http://serviceproduct/product/{pid}
    @GetMapping(value = "/product/{pid}")
    Product findByPid(@PathVariable("pid") Integer pid);
}

package com.zking.controller;
import com.alibaba.fastjson.JSON;
import com.zking.domain.Order;
import com.zking.domain.Product;
import com.zking.service.OrderService;
import com.zking.service.ProductService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
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 org.springframework.web.client.RestTemplate;
import java.util.List;
import java.util.Random;
@RestController
@Slf4j
public class OrderController {
    @Autowired
    private OrderService orderService;
    @Autowired
    private ProductService productService;
    //下单--fegin
    @RequestMapping("/order/prod/{pid}")
    public Order order(@PathVariable("pid") Integer pid) {
        log.info("接收到{}号商品的下单请求,接下来调用商品微服务查询此商品信息", pid);
        //调用商品微服务,查询商品信息
        Product product = productService.findByPid(pid);
        if (product.getPid() == -1) {
            Order order = new Order();
            order.setPname("下单失败");
            log.info("*******下单失败!稍后重试!");
            return order;
        }
        log.info("查询到{}号商品的信息,内容是:{}", pid, JSON.toJSONString(product));
        //下单(创建订单)
        Order order = new Order();
        order.setUid(1);
        order.setUsername("测试用户");
        order.setPid(pid);
        order.setPname(product.getPname());
        order.setPprice(product.getPprice());
        order.setNumber(1);
        orderService.createOrder(order);
        log.info("创建订单成功,订单信息为{}", JSON.toJSONString(order));
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return order;
    }
}

@RequestMapping("/order/prod/{pid}")
public Order order(@PathVariable("pid") Integer pid) {
    log.info("接收到{}号商品的下单请求,接下来调用商品微服务查询此商品信息", pid);
    //调用商品微服务,查询商品信息
    Product product = productService.findByPid(pid);
    if (product.getPid() == -1) {
      Order order = new Order();
      order.setPname("下单失败");
      return order;
    }
    log.info("查询到{}号商品的信息,内容是:{}", pid, JSON.toJSONString(product));
    //下单(创建订单)
    Order order = new Order();
    order.setUid(1);
    order.setUsername("测试用户");
    order.setPid(pid);
    order.setPname(product.getPname());
    order.setPprice(product.getPprice());
    order.setNumber(1);
    orderService.createOrder(order);
    log.info("创建订单成功,订单信息为{}", JSON.toJSONString(order));
    try {
      Thread.sleep(100);
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
    return order;
  }
}

<dependency>
  <groupId>com.alibaba.csp</groupId>
  <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
</dependency>

package com.zking.config;
import com.alibaba.csp.sentinel.adapter.gateway.common.SentinelGatewayConstants;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiDefinition;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiPathPredicateItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiPredicateItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.GatewayApiDefinitionManager;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.reactive.result.view.ViewResolver;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
import javax.annotation.PostConstruct;
import java.util.*;
@Configuration
public class GatewayConfiguration {
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;
    public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }
    // 初始化一个限流的过滤器
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }
    // 配置初始化的限流参数
    @PostConstruct
    public void initGatewayRules() {
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(
                new GatewayFlowRule("product_route") //资源名称,对应路由id
                        .setCount(1) // 限流阈值
                        .setIntervalSec(1) // 统计时间窗口，单位是秒，默认是 1 秒
        );
        GatewayRuleManager.loadRules(rules);
    }
    // 配置限流的异常处理器
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }
    //　自定义限流异常页面
    @PostConstruct
    public void initBlockHandlers() {
        BlockRequestHandler blockRequestHandler = new BlockRequestHandler() {
            public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) {
                Map map = new HashMap<>();
                map.put("code", 0);
                map.put("message", "接口被限流了");
                return ServerResponse.status(HttpStatus.OK).
                        contentType(MediaType.APPLICATION_JSON_UTF8).
                        body(BodyInserters.fromObject(map));
            }
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }
}

// 配置初始化的限流参数
    @PostConstruct
    public void initGatewayRules() {
//        Set<GatewayFlowRule> rules = new HashSet<>();
//        rules.add(
//                new GatewayFlowRule("product_route") //资源名称,对应路由id
//                        .setCount(1) // 限流阈值
//                        .setIntervalSec(1) // 统计时间窗口，单位是秒，默认是 1 秒
//        );
//        GatewayRuleManager.loadRules(rules);
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(new GatewayFlowRule("product_api1").setCount(1).setIntervalSec(1));
        rules.add(new GatewayFlowRule("product_api2").setCount(1).setIntervalSec(1));
        GatewayRuleManager.loadRules(rules);
    }
   
   //自定义API分组
    @PostConstruct
    private void initCustomizedApis() {
        Set<ApiDefinition> definitions = new HashSet<>();
        ApiDefinition api1 = new ApiDefinition("product_api1")
                .setPredicateItems(new HashSet<ApiPredicateItem>() {{
                    // 以/product-serv/product/api1 开头的请求
                    add(new ApiPathPredicateItem().setPattern("/product-serv/product/api1/**").
                            setMatchStrategy(SentinelGatewayConstants.URL_MATCH_STRATEGY_PREFIX));
                }});
        ApiDefinition api2 = new ApiDefinition("product_api2")
                .setPredicateItems(new HashSet<ApiPredicateItem>() {{
                    // 以/product-serv/product/api2/demo1 完成的url路径匹配
                    add(new ApiPathPredicateItem().setPattern("/product-serv/product/api2/demo1"));
                }});
        definitions.add(api1);
        definitions.add(api2);
        GatewayApiDefinitionManager.loadApiDefinitions(definitions);
    }