springcloud alibaba-sentinel初始化

　　搭建一个 服务模块用于 被sentinel监控，步骤如下：

　　1. 搭建模块

　　2. 添加依赖

<dependencies>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--    后续做持久化用到    -->
        <dependency>
            <groupId>com.alibaba.csp</groupId>
            <artifactId>sentinel-datasource-nacos</artifactId>
        </dependency>
        <!--   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>

        <!--  web组件      -->
        <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>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>cn.aib.springcloud</groupId>
            <artifactId>springclud-api-common</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

　　3. 添加配置

server:
  port: 8401
spring:
  application:
    name: cloudalibaba-sentinel-service
  cloud:
    nacos:
      discovery: #Nacos注册中心地址
        server-addr: localhost:8848
    sentinel:
      transport: #dashboard地址
        dashboard: localhost:8080
　　　　  port: 8719  #默认端口，如果被占用则从8719依次+1扫描；该端口是用于和sentinel交互的端口号

management: #暴露被监控端点
  endpoints:
    web:
      exposure:
        include: "*"

　　4. 主启动

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

　　5. 业务类

@RestController
@Slf4j
public class SentinelClientController {

    @GetMapping("/testA")
    public String testA(){
        try {
            TimeUnit.MILLISECONDS.sleep(800);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "---------testA";
    }

    @GetMapping("/testB")
    public String testB(){
        return "----------testB";
    }


}

　　6. 启动nacos，sentinel

　　7. 测试。这时我们访问sentinel前台界面，会发现没有该服务被监控，实际上sentinel采用的是懒加载，只有当服务被访问时才会显示。