SpringCloud Alibaba Sentinel实现熔断与限流

1、官网

https://github.com/alibaba/Sentinel

中文介绍 · alibaba/Sentinel Wiki (github.com)

2、是什么：一句话解释，之前我们讲解过的Hystrix

3、去哪下：https://github.com/alibaba/Sentinel/releases

4、能干嘛

5、怎么玩

https://spring-cloud-alibaba-group.github.io/github-pages/greenwich/spring-cloud-alibaba.html

服务使用中的各种问题：服务雪崩、服务降级、服务熔断、服务限流

安装Sentinel控制台

1、sentinel组件由2部分构成后台和前端8080

下载地址 https://github.com/alibaba/Sentinel/releases

下载到本地sentinel-dashboard-1.8.4.jar

前提 java8环境OK 8080端口没有被占用

命令行执行 java -jar sentinel-dashboard-1.8.4.jar

访问sentinel管理界面 http://localhost:8080 用户名密码均为sentinel

初始化工程

1、新建Module cloudalibaba-sentinel-service8401

2、pom文件

<dependencies>
        <!--SpringCloud ailibaba nacos -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--SpringCloud ailibaba sentinel-datasource-nacos 后续做持久化用到-->
        <dependency>
            <groupId>com.alibaba.csp</groupId>
            <artifactId>sentinel-datasource-nacos</artifactId>
        </dependency>
        <!--SpringCloud ailibaba sentinel -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!-- SpringBoot整合Web组件+actuator -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--日常通用jar包配置-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>4.6.3</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency><br></dependencies>

3、application.yml文件

server:
  port: 8401
 
spring:
  application:
    name: cloudalibaba-sentinel-service
  cloud:
    nacos:
      discovery:
        #Nacos服务注册中心地址
        server-addr: localhost:8848
    sentinel:
      transport:
        #配置Sentinel dashboard地址
        dashboard: localhost:8080
        #默认8719端口，假如被占用会自动从8719开始依次+1扫描,直至找到未被占用的端口
        port: 8719
 
management:
  endpoints:
    web:
      exposure:
        include: '*'

4、主启动类

@EnableDiscoveryClient
@SpringBootApplication
public class MainApp8401
{
    public static void main(String[] args) {
        SpringApplication.run(MainApp8401.class, args);
    }
}

5、业务类

@RestController
@Slf4j
public class FlowLimitController {

    @GetMapping("/testA")
    public String testA()
    {

        try { TimeUnit.SECONDS.sleep(800); } catch (InterruptedException e) { e.printStackTrace(); }

        return "------testA";
    }

    @GetMapping("/testB")
    public String testB()
    {
        log.info(Thread.currentThread().getName()+"\t"+"...testB");
        return "------testB";
    }

}