05.SpringCloud OpenFeign (服务接口调用)

1.概述

OpenFeign是什么

Feign是一个声明式的web服务客户端，让编写web服务客户端变得容易，只需创建一个接口并在接口上添加注解即可

https://github.com/spring-cloud/spring-cloud-openfeign

能干嘛

Feign和OpenFeign两者区别

2.OpenFeign使用步骤

核心：接口+注解

微服务调用接口+@FeignClient

新建cloud-consumer-feign-order80

Feign在消费端使用

pom

<?xml version="1.0" encoding="UTF-8"?>
<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>springcloud2020</artifactId>
        <groupId>com.chl.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-consumer-feign-order80</artifactId>

    <!--openfeign-->
    <dependencies>
        <!--openfeign的依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>com.chl.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <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>
    </dependencies>


</project>

yml

server:
  port: 80
eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka, http://eureka7002.com:7002/eureka

主启动类

@SpringBootApplication
@EnableFeignClients //开启openfeign的功能
public class OrderFeignMain80 {
    public static void main(String[] args) {
        SpringApplication.run(OrderFeignMain80.class,args);
    }
}

业务类

业务逻辑接口+@FeignClient配置调用provider服务

新建PaymentFeignService接口并新增注解@FeignClient

@Component
@FeignClient("CLOUD-PAYMENT-SERVICE") //对应的提供方的服务名
public interface PaymentFeignService {

    //要调用提供方的对应接口url  用调用本地的service方式调用 远端的服务
    @GetMapping("/payment/get/{id}")
    public CommonResult get(@PathVariable("id")Long id);
}

控制层Controller

@RestController
@Slf4j
public class OrderFeignController {

    @Autowired
    private PaymentFeignService paymentFeignService;

    @GetMapping("/consumer/payment/get/{id}")
    public CommonResult get(@PathVariable("id")Long id){
       return paymentFeignService.get(id);
    }
}

测试

先启动2个eureka集群7001/7002

再启动2个微服务8001/8002

启动OpenFeign order80启动

http://localhost/consumer/payment/get/1

Feign自带负载均衡配置项

小总结

3.OpenFeign超时控制

超时设置，故意设置超时演示出错情况

1.服务提供方8001故意写暂停程序

PaymentController新加测试方法

  /**
     * 故意写的服务提供方吃力业务要3秒，用于测试feign的超时问题
     * @return
     */
    @GetMapping(value = "/payment/feign/timeout")
    public String paymentFeignTimeout(){
        try { TimeUnit.SECONDS.sleep(3); }catch (Exception e) {e.printStackTrace();}
        return serverPort;
    }

2.服务消费方80添加超时方法PaymentFeignService

//测试feigin的超时问题
    @GetMapping(value = "/payment/feign/timeout")
    public String paymentFeignTimeout();

3.服务消费方80添加超时方法OrderFeignController

/**
     * 测试feigin的超时问题
     * @return
     */
    @GetMapping(value = "/consumer/payment/feign/timeout")
    public String paymentFeignTimeout(){
        return paymentFeignService.paymentFeignTimeout();
    }

4.测试

http://localhost/consumer/payment/feign/timeout

原因说明

OpenFeign默认等待一秒钟，超过后报错、

OpenFeign默认支持Ribbon

超时设置

ribbon:
  ReadTimeout:  5000 #请求连接的超时时间 5秒
  ConnectTimeout: 5000 #请求处理的超时时间 5秒

4.OpenFeign日志打印功能

日志打印功能

是什么

日志级别

配置日志bean

在消费端添加配置bean

@Configuration
public class FeignConfig {

    @Bean
    Logger.Level feignLoggerLevel(){
        return Logger.Level.FULL;
    }
}

YML文件里需要开启日志的Feign客户端

logging:
  level:
    com.chl.springcloud.service.PaymentFeignService: debug

测试