OpenFeign

OpenFeign

Feign是一个声明式的Web服务客户端，让编写Web服务端变得非常容易，只需要创建一个接口并在接口上添加注解即可。

OpenFeign服务调用

新建子项目(cloud-consumer-feign-order80)，修改pom.xml文件

<?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>cloud2020</artifactId>
        <groupId>com.atguigu.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

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

    <dependencies>
    <!--openfeign-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
    <!--eureka client-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
    <!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
    <dependency>
        <groupId>com.atguigu.springcloud</groupId>
        <artifactId>cloud-api-commons</artifactId>
        <version>${project.version}</version>
    </dependency>
    <!--web-->
    <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>
    <!--一般基础通用配置-->
    <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>

创建配置文件application.yml

server:
  port: 7999
eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002/eureka/

创建主启动类OrderFeignMain80

package com.atguigu.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;

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

创建PaymentFeignService接口

package com.atguigu.springcloud.service;

import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

@Component
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")
public interface PaymentFeginService {

    @GetMapping(value = "/payment/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id);
}

创建OrderFeignController

package com.atguigu.springcloud.controller;

import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import com.atguigu.springcloud.service.PaymentFeginService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@RestController
public class OrderFeignController {
    @Resource
    private PaymentFeginService paymentFeginService;

    @GetMapping(value = "/consumer/payment/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id){
        return paymentFeginService.getPaymentById(id);
    }
}

运行集群7001、7002，PaymentMain8001、8002，OrderFeignMain80

OpenFeign也可以达到负载均衡。

OpenFeign超时控制

在子项目(8001)的PaymentController添加

 @GetMapping(value = "/payment/feign/timeout")
    public String paymentFeignTimeout() {

        try {
            //暂停线程三秒钟
            TimeUnit.SECONDS.sleep(3);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return serverPort;
    }

在子项目(cloud-consumer-feign-order80)的PaymentFeignService添加

 @GetMapping(value = "/payment/feign/timeout")
    public String paymentFeignTimeout();

OrderFeignController添加

 @GetMapping(value = "/consumer/payment/feign/timeout")
    public String paymentFeignTimeout(){
        return paymentFeginService.paymentFeignTimeout();
    }

运行

出现时间超时错误

在子项目(cloud-consumer-feign-order80)的application.yml添加

#设置feign客户端超时时间(OpenFeign默认支持ribbon)
ribbon:
  ReadTimeout: 5000       #指的是建立连接所用的时间，适用于网络状况正常的情况下，两端连接所用的时间
  ConnecTimeout: 5000     #指的是建立连接后从服务器读取到可用资源所用的时间

运行

OpenFeign日志增强

Feign提供了日志打印功能，我们可以通过配置来调整日志级别，从而了解Feign中Http请求的细节。说白了就是对Feign接口的调用情况进行监控和输出。

日志级别

NONE：默认的，不显示任何日志；

BASIC：仅记录请求方法、URL、响应状态码及执行时间；

HEADERS：除了BASIC中定义的信息之外，还有请求和响应的头信息；

FULL：除了HEADERS中定义的信息之外，还有请求和响应的正文及源数据；

在子项目(cloud-consumer-feign-order80)创建一个配置类FeignConfig

package com.atguigu.springcloud.config;

import feign.Logger;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class FeignConfig {

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

修改application.yml

logging:
  level:
    com.atguigu.springcloud.service.PaymentFeginService: debug      #feign日志以什么级别监控哪个接口

运行查看