初始化监控

1.搭建Sentinel项目

1. Sentinel的官方文档网址：https://sentinelguard.io/zh-cn/docs/quick-start.html

2. 创建项目sentinel-service-8401

3. 导入依赖

   <?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
       <modelVersion>4.0.0</modelVersion>
   
       <parent>
           <groupId>com.zt.studydemo</groupId>
           <artifactId>study_demo</artifactId>
           <version>0.0.1-SNAPSHOT</version>
           <relativePath/> <!-- lookup parent from repository -->
       </parent>
   
       <artifactId>sentinel-service-8401</artifactId>
       <version>0.0.1-SNAPSHOT</version>
       <name>sentinel-service-8401</name>
       <description>sentinel-service-8401</description>
   
       <properties>
           <java.version>1.8</java.version>
       </properties>
   
       <dependencies>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-web</artifactId>
           </dependency>
   
           <!-- Nacos客户端依赖 -->
           <dependency>
               <groupId>com.alibaba.cloud</groupId>
               <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
           </dependency>
   
           <!-- sentinel依赖 -->
           <dependency>
               <groupId>com.alibaba.cloud</groupId>
               <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
           </dependency>
       </dependencies>
   
       <build>
           <plugins>
               <plugin>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-maven-plugin</artifactId>
               </plugin>
           </plugins>
       </build>
   
   </project>
   
   

4. 配置yml

   server:
     port: 8401
   
   spring:
     main:
       allow-circular-references: true
     application:
       name: sentinel-service-8401
     cloud:
       nacos:
         discovery:
           server-addr: 192.168.56.10:3333
       sentinel:
         transport:
           # 配置Sentinel dashboard地址
           dashboard: localhost:8080
           # 默认8719端口，键入被占用会自动从8719+1，直到找到未被占用的端口
           port: 8719
   
   management:
     endpoints:
       web:
         exposure:
           include: '*'
   

5. 编写FlowLimitController

   import org.springframework.web.bind.annotation.GetMapping;
   import org.springframework.web.bind.annotation.RestController;
   
   @RestController
   public class FlowLimitController {
   
       @GetMapping("/testA")
       public String testA() {
           return "-----testA";
       }
   
       @GetMapping("/testB")
       public String testB() {
           return "-----testB";
       }
   }
   

2.测试

1. 启动nacos

2. 启动sentinel

3. 启动8401应用，此时应该在Sentinel的dashboard上能体现出它监控的服务，但是此时并没有，原因是因为Sentinel本身采用的是懒加载机制，所以我们需要首先访问服务对应的接口，Sentinel才能工作。

4. 访问接口

   http://localhost:8401/testA
   http://localhost:8401/testB
   

5. 查看Sentinel的dashboard