SpringCloudAlibaba-16-sentinel整合feign实现服务调用

前言

使用sentinel实现服务间的调用,sentinel在这里面作为了是流量防护组件。他结合openfeign实现了服务降级等作用。以下我们创建结合sentinel和feign的创建2个应用，服务消费方，服务提供方。

内容

服务提供方:provider创建

1.创建spring项目
2.引入cloud依赖

<!--依赖版本定义-->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.1.1.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
```  
4. 4.使用sentinel、openfeign、discovery

com.alibaba.cloud
spring-cloud-starter-alibaba-nacos-discovery

com.alibaba.cloud
spring-cloud-starter-alibaba-sentinel

org.springframework.cloud
spring-cloud-starter-openfeign

1
2
3


5. 5.我们是服务提供方,我们书写一个接口

@RestController
public class DemoController {
@GetMapping(“/feign”)
public String feign(){
return “hello sentinel feign”;
}
}

1 2	6. 6.启动类添加注解

@SpringCloudApplication
public class SentinelFeignProviderApplication {
public static void main(String[] args) {
SpringApplication.run(SentinelFeignProviderApplication.class, args);
}
}

1 2	7. 7.添加配置文件application.yml

server:
port: 18082
spring:
application:
name: sentinel-feign-provider
cloud:
nacos:
discovery:
server-addr: 127.0.0.1:8848


#### 服务消费方:consumer创建  
我们复制sentinel-feign-provider修改成 sentinel-feign-consumer  
启动类上添加注解:@EnableFeignClients  
1. 1.创建feign客户端

@FeignClient(value = “sentinel-feign-provider”,fallback =DemoFeignClientFallback.class)
public interface DemoFeginClient {
@GetMapping(“/feign”)
String feign();
}

1
2
3


2. 2.创建服务降级实现类

@Component
public class DemoFeignClientFallback implements DemoFeginClient {
@Override
public String feign() {
return “error”;
}
}

1 2	3. 3.创建consumer的测试请求类:

@RestController
public class DemoController {
@Autowired
private DemoFeginClient demoFeginClient;
@GetMapping(“/hello”)
public String feign(){
return demoFeginClient.feign();
}
}
```

测试:
http://localhost:18083/hello
结果：
hello sentinel feign

2020-02-02