sentinel下载、安装、使用、循环引用异常

官网：https://sentinelguard.io/zh-cn/index.html
注解支持：https://github.com/alibaba/Sentinel/wiki/%E6%B3%A8%E8%A7%A3%E6%94%AF%E6%8C%81
sentinel控制台文档：https://sentinelguard.io/zh-cn/docs/dashboard.html
参考：https://www.cnblogs.com/ralgo/p/14152390.html
1、下载sentinel-dashboard.jar，下载地址：https://github.com/alibaba/Sentinel/releases
并启动，cmd执行命令，最后面是jar包路径：java -Dserver.port=8080 -Dcsp.sentinel.dashboard.server=localhost:8080 -Dproject.name=sentinel-dashboard -jar E:\download\sentinel-dashboard-1.8.3.jar
浏览器访问 http://localhost:8080，登录账号密码都是sentinel
2、项目的pom

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>cloud22</artifactId>
        <groupId>com.jay.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-provider-payment8001</artifactId>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-parent</artifactId>
                <version>2.6.4</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>2021.0.1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2021.0.1.0</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <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>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            <version>2021.1</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-bootstrap</artifactId>
            <version>3.1.1</version>
        </dependency>
        <!--        不需要引用这些，仅仅引用 com.alibaba.cloud/spring-cloud-starter-alibaba-sentinel/2.1.0.RELEASE 就可以，版本号高了会导致jar包循环引用的问题-->
        <!--        <dependency>-->
        <!--            <groupId>com.alibaba.csp</groupId>-->
        <!--            <artifactId>sentinel-core</artifactId>-->
        <!--            <version>1.8.3</version>-->
        <!--        </dependency>-->
        <!--        <dependency>-->
        <!--            <groupId>com.alibaba.csp</groupId>-->
        <!--            <artifactId>sentinel-annotation-aspectj</artifactId>-->
        <!--            <version>1.8.3</version>-->
        <!--        </dependency>-->
        <!--        <dependency>-->
        <!--            <groupId>com.alibaba.csp</groupId>-->
        <!--            <artifactId>sentinel-transport-simple-http</artifactId>-->
        <!--            <version>1.8.3</version>-->
        <!--        </dependency>-->

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
            <version>2.1.0.RELEASE</version>
        </dependency>

        <!--        <dependency>-->
        <!--            <groupId>com.alibaba.csp</groupId>-->
        <!--            <artifactId>sentinel-datasource-nacos</artifactId>-->
        <!--            <version>1.8.3</version>-->
        <!--        </dependency>-->


        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
        </dependency>
        <!--mysql-connector-java-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--jdbc-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </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>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
        </dependency>
        <dependency>
            <groupId>com.jay.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</project>

 yaml修改了，增加了sentinel那一段的配置

server:
  port: 8001
spring:
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #Nacos作为服务中心地址
      config:
        server-addr: localhost:8848
        file-extension: yaml
        group: SH_GROUP
        namespace: test
    sentinel:
      transport:
        dashboard: localhost:9090 #配置sentinel dashboard地址，监控项目端口8001
        port: 8719 #默认8719端口，如果被占用，则从8719递增检查未被占用的端口
  application:
    name: cloud-payment-service #cloud-payment-service-dev.yaml
  profiles:
    active: test

#${prefix}-${spring.profiles.active}.${file-extension}

服务端代码示例：当热点规则配置 每秒1次，超过就会走dealGetPaymentById方法，deal方法的返回值和引用方法一样，参数多了一个 BlockException

/**
     * SentinelResource 在 sentinel 网页中配置热点(HotKey)的时候使用 value，保持唯一，
     * blockHandler 是在 getPaymentById 方法异常后的处理方法
     */
    @SentinelResource(value = "PaymentController.getPaymentById", blockHandler = "dealGetPaymentById")
    @GetMapping(value = "/payment/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable(value = "id", required = true) Long id) {
        Payment payment = paymentService.getPaymentById(id);
        if (payment != null) {
            return new CommonResult(200, "查询成功,serverPort:  " + serverPort, payment);
        } else {
            return new CommonResult(444, "没有对应记录,查询ID: " + id, null);
        }
    }

    /**
     * sentinel 限流处理
     */
    public CommonResult<Payment> dealGetPaymentById(Long id, BlockException ex) {
        return new CommonResult(555, "Sentinel HotKey限流: " + id, null);
    }

 @SentinelResource中还可以配置fallback，服务如果出现异常，走fallback指定的方法处理异常Throwable。自定义异常处理。
如果同时配置了fallback和blockHandler，当超过sentinel的流控规则时，流控规则blockHandler优先，否则走fallback。
配置exceptionsToIgnore指定fallback不处理哪些异常。

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-feign</artifactId>
    <version>1.4.7.RELEASE</version>
</dependency>

ymal：feign.sentinel.enabled = true
启动类：@EnableFeignClients，消费端interface加@FeignClient(value = "服务id",fallback=xxx.class)，例如：payment-service，
xxx实现interface，其中的实现就是运行出错时的处理类。
参考：https://www.bilibili.com/video/BV18E411x7eT?p=136
保持接口和服务端签名一致，加注解，例如@GetMapping(value = "服务的调用路径 payment/get/{id}")。
sentinel持久化：https://www.bilibili.com/video/BV18E411x7eT?p=138

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-datasource-nacos</artifactId>
    <version>1.8.0</version>
</dependency>

ymal：

前缀：spring.cloud.sentinel

dataSource
 ds1:
  nacos:
   server-addr: localhost:8848
   dataId: cloudalibaba-sentinel-service
   groupId: DEFAULT_GROUP
   data-type: json
   rule-typle: flow