Spring Cloud Alibaba | Sentinel：分布式系统的流量防卫兵进阶实战

在阅读本文前，建议先阅读《Spring Cloud Alibaba | Sentinel：分布式系统的流量防卫兵基础实战》。

1. Sentinel整合Feign和RestTemplate

Sentinel目前已经同时支持Feign和RestTemplate，需要我们引入对应的依赖，在使用Feign的时候需要在配置文件中打开Sentinel对Feign的支持：feign.sentinel.enabled=true，同时需要加入openfeign starter依赖使sentinel starter中的自动化配置类生效。在使用RestTemplate的时候需要在构造RestTemplate的Bean的时候加上@SentinelRestTemplate注解，开启Sentinel对RestTemplate的支持。

1.1 创建父工程sentinel-springcloud-high：

父工程pom.xml如下：

代码清单：Alibaba/sentinel-springcloud-high/pom.xml
***

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<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>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>

公共组件中引入Sentinel做流量控制，引入Nacos做服务中心。

1.2 创建子工程provider_server：

配置文件application.yml如下：

代码清单：Alibaba/sentinel-springcloud-high/provider_server/pom.xml
***

server:
  port: 8000
spring:
  application:
    name: spring-cloud-provider-server
  cloud:
    nacos:
      discovery:
        server-addr: 192.168.44.129:8848
    sentinel:
      transport:
        dashboard: localhost:8080
        port: 8720
management:
  endpoints:
    web:
      cors:
        allowed-methods: '*'

接口测试类HelloController.java如下：

代码清单：Alibaba/sentinel-springcloud-high/provider_server/src/main/java/com/springcloud/provider_server/controller/HelloController.java
***

@RestController
public class HelloController {
    @GetMapping("/hello")
    public String hello(HttpServletRequest request) {
        return "Hello, port is: " + request.getLocalPort();
    }
}

1.3 创建子工程consumer_server：

子工程依赖pom.xml如下：

代码清单：Alibaba/sentinel-springcloud-high/consumer_server/pom.xml
***

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

配置文件application.yml如下：

代码清单：Alibaba/sentinel-springcloud-high/consumer_server/src/main/resources/application.yml
***

server:
  port: 9000
spring:
  application:
    name: spring-cloud-consumer-server
  cloud:
    nacos:
      discovery:
        server-addr: 192.168.44.129:8848
    sentinel:
      transport:
        dashboard: localhost:8080
        port: 8719
management:
  endpoints:
    web:
      cors:
        allowed-methods: '*'
feign:
  sentinel:
    enabled: true

这里使用feign.sentinel.enabled=true开启Sentinel对Feign的支持。

接口测试类HelloController.java

代码清单：Alibaba/sentinel-springcloud-high/consumer_server/src/main/java/com/springcloud/consumer_server/controller/HelloController.java
***

@RestController
public class HelloController {
    @Autowired
    HelloRemote helloRemote;

    @Autowired
    RestTemplate restTemplate;

    @GetMapping("/helloByFeign")
    public String helloByFeign() {
        return helloRemote.hello();
    }

    @GetMapping("/helloByRestTe