SpringCloud第十八章AlibabaSentinel实现熔断与限流（@SentinelResource）

8、@SentinelResource

8.1、按资源名称限流+后续处理

• 启动Nacos成功 http://localhost:8848/nacos/#/login

• 启动Sentinel成功 java -jar sentinel-dashboard-1.7.0.jar

• Module

  • cloudalibaba-sentinel-service8401

  • POM

    
    <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>mscloud03artifactId>
            <groupId>com.atguigu.springcloudgroupId>
            <version>1.0-SNAPSHOTversion>
        parent>
        <modelVersion>4.0.0modelVersion>
    
        <artifactId>cloudalibaba-sentinel-service8401artifactId>
          <dependencies>
          
          <dependency>
              <groupId>com.alibaba.cloudgroupId>
              <artifactId>spring-cloud-starter-alibaba-nacos-discoveryartifactId>
          dependency>
          <dependency>
              <groupId>com.atguigu.springcloudgroupId>
              <artifactId>cloud-api-commonsartifactId>
              <version>${project.version}version>
          dependency>
          
          <dependency>
              <groupId>com.alibaba.cspgroupId>
              <artifactId>sentinel-datasource-nacosartifactId>
          dependency>
          
          <dependency>
              <groupId>com.alibaba.cloudgroupId>
              <artifactId>spring-cloud-starter-alibaba-sentinelartifactId>
          dependency>
          
          <dependency>
              <groupId>org.springframework.cloudgroupId>
              <artifactId>spring-cloud-starter-openfeignartifactId>
          dependency>
          
          <dependency>
              <groupId>org.springframework.bootgroupId>
              <artifactId>spring-boot-starter-webartifactId>
          dependency>
          <dependency>
              <groupId>org.springframework.bootgroupId>
              <artifactId>spring-boot-starter-actuatorartifactId>
          dependency>
          
          <dependency>
              <groupId>org.springframework.bootgroupId>
              <artifactId>spring-boot-devtoolsartifactId>
              <scope>runtimescope>
              <optional>trueoptional>
          dependency>
          <dependency>
              <groupId>cn.hutoolgroupId>
              <artifactId>hutool-allartifactId>
              <version>4.6.3version>
          dependency>
          <dependency>
              <groupId>org.projectlombokgroupId>
              <artifactId>lombokartifactId>
              <optional>trueoptional>
          dependency>
          <dependency>
              <groupId>org.springframework.bootgroupId>
              <artifactId>spring-boot-starter-testartifactId>
              <scope>testscope>
          dependency>
    
      dependencies>
    project>
    

  • YML

    server:
     port: 8401
    
    spring:
      application:
        name: cloudalibaba-sentinel-service
      cloud:
        nacos:
          discovery:
            server-addr: localhost:8848 #Nacos服务注册中心地址
        sentinel:
          transport:
            dashboard: localhost:8080 #配置Sentinel dashboard地址
            port: 8719
    
    management:
      endpoints:
        web:
          exposure:
            include: '*'
    
    

  • 业务类RateLimitController

    package com.atguigu.springcloud.alibaba.controller;
    
    import com.alibaba.csp.sentinel.annotation.SentinelResource;
    import com.alibaba.csp.sentinel.slots.block.BlockException;
    import com.atguigu.springcloud.entities.CommonResult;
    import com.atguigu.springcloud.entities.Payment;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
      @RestController
      public class RateLimitController
      {
          @GetMapping("/byResource")
          @SentinelResource(value = "byResource",blockHandler = "handleException")
          public CommonResult byResource()
          {
              return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001"));
          }
          public CommonResult handleException(BlockException exception)
          {
              return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
          }
      }
    

    • 主启动

   package com.atguigu.springcloud.alibaba;
   
     import org.springframework.boot.SpringApplication;
     import org.springframework.boot.autoconfigure.SpringBootApplication;
     import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
     import org.springframework.cloud.openfeign.EnableFeignClients;
   
   
     @EnableDiscoveryClient
     @SpringBootApplication
     public class MainApp8401
     {
         public static void main(String[] args) {
             SpringApplication.run(MainApp8401.class, args);
         }
     }
   
  

• 配置流控规则

  • 配置步骤

    

  • 图形配置和代码关系

    

  • 表示1秒钟内查询次数大于1，就跑到我们自定义的处流，限流

• 测试

  • 1秒钟点击1下，OK

  • 超过上述，疯狂点击，返回了自己定义的限流处理信息，限流发生

    

• 额外问题

  • 此时关闭问服务8401看看
  • Sentinel控制台，流控规则消失了？？？？？
    • 临时/持久？

8.2、按照Url地址限流+后续处理

• 通过访问的URL来限流，会返回Sentinel自带默认的限流处理信息

• 业务类RateLimitController

  package com.atguigu.springcloud.alibaba.controller;
  
  import com.alibaba.csp.sentinel.annotation.SentinelResource;
  import com.alibaba.csp.sentinel.slots.block.BlockException;
  import com.atguigu.springcloud.entities.CommonResult;
  import com.atguigu.springcloud.entities.Payment;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.RestController;
  
  @RestController
  public class RateLimitController
  {
      @GetMapping("/byResource")
      @SentinelResource(value = "byResource",blockHandler = "handleException")
      public CommonResult byResource()
      {
          return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001"));
      }
      public CommonResult handleException(BlockException exception)
      {
          return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
      }
  
      @GetMapping("/rateLimit/byUrl")
      @SentinelResource(value = "byUrl")
      public CommonResult byUrl()
      {
          return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
      }
  }
   
  

• 访问一次 http://localhost:8401/rateLimit/byUrl

• Sentinel控制台配置

  

• 测试

  • 疯狂点击http://localhost:8401/rateLimit/byUrl

  • 结果

    会返回Sentinel自带的限流处理结果

    

8.3、上面兜底方案面临的问题

• 系统默认的，没有体现我们自己的业务要求。
• 依照现有条件，我们自定义的处理方法又和业务代码耦合在一块，不直观。
• 每个业务方法都添加一个兜底的，那代码膨胀加剧。
• 全局统一的处理方法没有体现。

8.4、客户自定义限流处理逻辑

• 创建CustomerBlockHandler类用于自定义限流处理逻辑

• 自定义限流处理类

  CustomerBlockHandler

  package com.atguigu.springcloud.alibaba.myhandler;
  
  import com.alibaba.csp.sentinel.slots.block.BlockException;
  import com.atguigu.springcloud.alibaba.entities.CommonResult;
  import org.springframework.stereotype.Component;
  
  
  public class CustomerBlockHandler
  {
      public static CommonResult handleException(BlockException exception){
          return new CommonResult(2020,"自定义的限流处理信息......CustomerBlockHandler");
      }
  }
   
  

• RateLimitController

  package com.atguigu.springcloud.alibaba.controller;
  
  import com.alibaba.csp.sentinel.annotation.SentinelResource;
  import com.alibaba.csp.sentinel.slots.block.BlockException;
  import com.atguigu.springcloud.alibaba.myhandler.CustomerBlockHandler;
  import com.atguigu.springcloud.entities.CommonResult;
  import com.atguigu.springcloud.entities.Payment;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.RestController;
  
  
  @RestController
  public class RateLimitController
  {
      @GetMapping("/byResource")
      @SentinelResource(value = "byResource",blockHandler = "handleException")
      public CommonResult byResource()
      {
          return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001"));
      }
      public CommonResult handleException(BlockException exception)
      {
          return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
      }
  
      @GetMapping("/rateLimit/byUrl")
      @SentinelResource(value = "byUrl")
      public CommonResult byUrl()
      {
          return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
      }
  
      /**
       * 自定义通用的限流处理逻辑，
       blockHandlerClass = CustomerBlockHandler.class
       blockHandler = handleException2
       上述配置：找CustomerBlockHandler类里的handleException2方法进行兜底处理
       */
      /**
       * 自定义通用的限流处理逻辑
       */
      @GetMapping("/rateLimit/customerBlockHandler")
      @SentinelResource(value = "customerBlockHandler",
              blockHandlerClass = CustomerBlockHandler.class, blockHandler = "handleException2")
      public CommonResult customerBlockHandler()
      {
          return new CommonResult(200,"按客户自定义限流处理逻辑");
      }
  
  }
   
  

• 启动微服务后先调用一次

  http://localhost:8401/rateLimit/customerBlockHandler

• Sentinel控制台配置

  

• 测试后我们自定义的出来了

• 进一步说明

  

8.5、更多注解属性说明

• 多说一句

  

• Sentinel主要有三个核心Api

  • SphU定义资源
  • Tracer定义统计
  • ContextUtil定义了上下文