1.下载Sentinel.jar可以图形界面配置限流和降级规则
地址:可能需要翻墙
下载jar文件
2.引入maven依赖

   <!--    spring cloud gateway整合sentinel的依赖-->
   <dependency>
       <groupId>com.alibaba.cloud</groupId>
       <artifactId>spring-cloud-alibaba-sentinel-gateway</artifactId>
       <version>2.2.2.RELEASE</version>
   </dependency>

   <!--    sentinel的依赖-->
   <dependency>
       <groupId>com.alibaba.cloud</groupId>
       <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
       <version>2.2.2.RELEASE</version>
   </dependency>
   <dependency>
       <groupId>com.alibaba.csp</groupId>
       <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
       <version>1.8.0</version>
   </dependency>

3.写个自动注入Resource的过滤器类(可以不写注解直接使用)

@Configuration
public class GatewayConfiguration {
 
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;
 
    public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }
 
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        // Register the block exception handler for Spring Cloud Gateway.
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }
 
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }
}

4.写配置文件 application.properties

# 服务端口
server.port=80
# 服务名
spring.application.name=service-gateway
#服务熔断
spring.cloud.sentinel.transport.dashboard=localhost:18080
# nacos服务地址
spring.cloud.nacos.discovery.server-addr=192.168.56.1:8848
spring.main.allow-bean-definition-overriding=true
spring.profiles.active=dev

#使用服务发现路由
spring.cloud.gateway.discovery.locator.enabled=true

#设置路由id
spring.cloud.gateway.routes[0].id=service-cmn
#设置路由的uri
spring.cloud.gateway.routes[0].uri=lb://service-cmn
#设置路由断言,代理servicerId为auth-service的/auth/路径
spring.cloud.gateway.routes[0].predicates= Path=/*/cmn/**

5.cmd命令行启动jar文件访问localhost:18080页面,自己设置QPS
java -jar -server.port=18080 sentinel-dashboard.jar


--------不在微服务中使用,在普通springboot也可以使用--------
1.maven依赖

  <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</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>

2.service中写

@Service

public class UserService { 
	//不可以用在类上
    @SentinelResource(value = "sayHello",fallback = "sayHellofail")
    public String sayHello(){
        return "Hello,World";
    }

    public  String sayHellofail(){ //限流的方法
        return "I'am sorry";
    }

}

3.controller

@RestController
public class UserController {

    @Autowired
    UserService userService;

    @RequestMapping("/hello")
    public String hello(){
      return userService.sayHello();
    }
}

3.sentinel控制台查看

//快速访问