spring-cloud05--OpenFeign

1.OpenFeign是什么

　　Feign是一个声明式的web服务客户端，让编写web服务客户端变得非常容易，只需创建一个接口并在接口上添加注解即可。创建的这个接口通过@FeignClient注解去把服务端的口暴暴露出来。用于服务调用。

2.简要说明

　　2.1现有服务端，服务名称为CLOUD-PAYMENT-SERVICE，它提供了下面的服务接口

@GetMapping(value = "/payment/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") Long id) throws InterruptedException {
        TimeUnit.SECONDS.sleep(3);
        Payment payment = paymentService.getPaymentById(id);
        log.info("*****查询结果："+payment);
        if (payment!=null){  //说明有数据，能查询成功
            return new CommonResult(200,"查询成功" + serverport,payment);
        }else {
            return new CommonResult(444,"没有对应记录，查询ID："+id,null);
        }
    }

 

　　2.2在消费者端通过RestTemplate消费

public static final String PAYMENT_URL = "http://CLOUD-PAYMENT-SERVICE";
@GetMapping("/consumer/payment/get/{id}")
    public CommonResult<Payment> getPayment(@PathVariable("id") Long id){
        return restTemplate.getForObject(PAYMENT_URL+"/payment/get/"+id,CommonResult.class);
    }

　　这里我们是采用restTemplate去调用服务的接口，如果想要按照习惯性编码，用消费者端service去调用服务端的接口，就可以使用OpenFeign

 

3.使用

　　3.1加入依赖

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

 

　　完整依赖

　　

<?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>


        <dependency>
            <groupId>com.atguigu.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>${project.version}</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web  -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>


        <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>


    </dependencies>

</project>

 

 

4.yml配置

　　(注册中心用的Eureka)

server:
  port: 80

eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  #集群版

 

 

 

5.创建一个service，使用@FeignClient注解　

package com.atguigu.springcloud.service;

import com.atguigu.springcloud.entities.CommonResult;
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;

/**
 * @Classname PaymentFeignService
 * @Description TODO
 * @Date 2021/4/26 0026 下午 4:24
 * @Created by jcc
 */

@Component
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")  //value - 服务的名称
public interface PaymentFeignService {

    //这个接口是CLOUD-PAYMENT-SERVICE服务下提供的接口
    @GetMapping(value = "/payment/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") Long id);
}

　　@FeignClient的value属性为服务端的名称，这个service下的接口和服务端的接口一样，这样子这个service就代理了服务端的接口，直接通过这个service就可以调用服务端的接口

6.调用　

package com.atguigu.springcloud.controller;

import com.atguigu.springcloud.service.PaymentFeignService;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;

@RestController
@Slf4j
public class OrderController {

    @Resource
    private PaymentFeignService paymentFeignService;


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

}

 

　　这样子就完成了基本的调用

7.配置超时时间

　　Fegin的默认的调用服务端额超时时间为1秒，超过这个时间服务没有返回的，直接报错，但是，有时候有些服务的调用事件会比较长，就需要对超时时间进行配置

　　加入配置　　

feign:
 client:
  config:
   default:
        #简历连接所用的时间，适用于网络状况正常的情况下，两端连接所需要的时间
        ConnectTimeOut: 5000
        #指建立连接后从服务端读取到可用资源所用的时间
        ReadTimeOut: 10000

 

　　完整配置

server:
  port: 80

eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  #集群版



feign:
 client:
  config:
   default:
        #简历连接所用的时间，适用于网络状况正常的情况下，两端连接所需要的时间
        ConnectTimeOut: 5000
        #指建立连接后从服务端读取到可用资源所用的时间
        ReadTimeOut: 10000

 

 

8.日志打印

　　当我们需要知道fegin的详细的工作过程的时候，可以打开fegin的日志功能

　　  它的日志有下面四个级别

　　

 

 

　　8.1创建配置类

package com.atguigu.springcloud.config;

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

/**
 * @Classname FeignConfig
 * @Description TODO
 * @Date 2021/4/26 0026 下午 5:04
 * @Created by jcc
 */
@Configuration
public class FeignConfig {
    @Bean
    Logger.Level feignLoggerLevel(){
    return Logger.Level.FULL;
     }
}

 

　　8.2配置文件

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

　　　　完整配置　

server:
  port: 80

eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  #集群版

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

feign:
 client:
  config:
   default:
        #简历连接所用的时间，适用于网络状况正常的情况下，两端连接所需要的时间
        ConnectTimeOut: 5000
        #指建立连接后从服务端读取到可用资源所用的时间
        ReadTimeOut: 10000

　　完成，此时已经打印详细功能