Version: Next

OpenFeign 服务调用

Open Feign 使用步骤

  1. 接口 + 注解： 微服务调用接口 + @FeignClient
  2. 新建 cloud-consumer-feign-order80

POM

<!-- openfeign -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
完整pom依赖
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--监控-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!--热部署-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</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>org.example</groupId>
<artifactId>cloud-api-commons</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<!--eureka client-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<!-- openfeign -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
</dependencies>

application.yaml

server:
port: 80
#这里只把feign做客户端用，不注册进eureka
eureka:
client:
#表示是否将自己注册进EurekaServer默认为true
register-with-eureka: false
service-url:
#defaultZone: http://localhost:7001/eureka
defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/

主启动类

添加注解

  • @EnableFeignClients
@SpringBootApplication
@EnableFeignClients
public class OrderFeignMain80 {
public static void main(String[] args) {
SpringApplication.run(OrderFeignMain80.class, args);
}
}

业务类

  1. 业务逻辑接口 + @FeignClient 配置调用 provider 服务
  2. 新建 PaymentFeignService 接口，并新增注解 @FeignClient
  3. 编写 Controller

正常创建 Service 层的接口 PaymentFeignService

  • @FeignClient(value = "要调用的服务名称" 注解
  • 用 GetMapping、PostMapping 指定对方微服务 Controller 暴露的路由地址即可（直接调对方 Service 方法也行），与 Spring MVC 画风一致
Service 层接口
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")
public interface PaymentFeignService {
@GetMapping(value = "/payment/get/{id}")
CommonResult<Payment> getPaymentById(@PathVariable("id") Long id);
}

Controller

  • 注入 Service 层

  • 书写Controller方法，通过 OpenFeign 去 Eureka 注册中心找具体微服务节点，然后调用这个节点的 Controller 方法

@RestController
@Slf4j
public class OrderFeignController {
@Resource
private PaymentFeignService paymentFeignService;
@GetMapping("/consumer/payment/get/{id}")
public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id) {
// 通过 openFeign 去 Eureka 找微服务，调那个微服务的 Controller 接口
return paymentFeignService.getPaymentById(id);
}
}

测试

  • 启动 Eureka 注册中心节点 7001、7002
  • 启动 provider8001、provider8002
  • 启动 consumer-feign-order80
  • 访问 localhost:80/consumer/payment/get/2
响应
{
"code": 200,
"message": "查询成功，端口号: 8081",
"data": {
"id": 2,
"serial": "长大002"
}
}
  • 多次访问，可以发现端口号是轮询的，8001、8002 交替
  • Feign 自带负载均衡配置项