从零开始学springcloud微服务项目 注意事项：

• 约定 > 配置 > 编码
• IDEA版本2021.1
• 这个项目，我分了很多章节，每篇文章都有一个操作步骤，目的是看起来更简单清晰
• controller调service，service调dao
• 项目源代码及sentinel安装包

1 Spring Cloud Ribbon是基于Netflix Ribbon一套客户端负载均衡的工具

1 OpenFeign集成了Ribbon

• 利用Ribbon维护了Payment通过轮询实现客户端负载平衡的服务列表信息。Ribbon不同的是，通过feign服务调用只需要定义服务绑定接口并以声明的方式进行，优雅简单 2 新增module 3 选择jdk1.8 4 输入服务名：cloud-consumer-feign-order80

5 复制cloud-consumer-order80到cloud-consumer-feign-order80 更改pom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>springcloud2022</artifactId>         <groupId>com.yg</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>         <dependency><!-- 引入自定义api一般包，可用Payment支付Entity -->             <groupId>com.yg</groupId>             <artifactI>cloud-api-commons</artifactId>
            <version>${project.version}</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>

更改application文件，添加超时连接控制和日志增强

server:
  port: 80


spring:
  application:
    name: cloud-consumer-order


eureka:
  client:
    #表示是否将自己注册进EurekaServer默认为true。
    register-with-eureka: true
    #是否从EurekaServer抓取已有的注册信息，默认为true。单节点无所谓，集群必须设置为true才能配合ribbon使用负载均衡
    fetchRegistry: true
    service-url:
      #defaultZone: http://localhost:7001/eureka
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka
  instance:
    instance-id: order80
    prefer-ip-address: true     #访问路径可以显示IP地址

#设置feign客户端超时时间(OpenFeign默认支持ribbon)
ribbon:
  #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
  ReadTimeout: 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
  ConnectTimeout: 5000

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

更改启动类

package com.yg.springcloud;

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

/** * @Author suolong * @Date 2022/6/15 15:10 * @Version 2.0 */
@EnableEurekaClient
@EnableFeignClients
@SpringBootApplication
public class FeignMainApp80 { 
        

    public static void main(String[] args) { 
        
        SpringApplication.run(FeignMainApp80.class);
    }

}

添加openFeign的日志打印配置

package com.yg.springcloud.config;

import feign.Logger;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

/** * @Author suolong * @Date 2022/6/15 20:53 * @Version 2.0 */
@Configuration
public class ApplicationContextConfig { 
        

    @Bean
    @LoadBalanced // 使用@LoadBalanced注解赋予RestTemplate负载均衡的能力
    public RestTemplate restTemplate()
    { 
        
        return new RestTemplate();
    }


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

}

更改controller

package com.yg.springcloud.controller;

import com.yg.springcloud.entities.CommonResult;
import com.yg.springcloud.entities.Payment;
import com.yg.springcloud.service.PaymentFeignService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;

/** * @Author suolong * @Date 2022/6/15 20:54 * @Version 2.0 */

@RestController
public class OrderController { 
        


    //public static final String PaymentSrv_URL = "http://localhost:8001";
    public static final String PaymentSrv_URL = "http://CLOUD-PAYMENT-SERVICE";


    @Autowired
    private RestTemplate restTemplate;


    @Resource
    private PaymentFeignService paymentFeignService;

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

    @GetMapping("/consumer/payment/create") //客户端用浏览器是get请求，但是底层实质发送post调用服务端8001
    public CommonResult create(Payment payment) { 
        
        return restTemplate.postForObject(PaymentSrv_URL + "/payment/create", payment, CommonResult.class);
    }


    @GetMapping("/consumer/payment/get/{id}")
    public CommonResult getPayment(@PathVariable Long id) { 
        
        return restTemplate.getForObject(PaymentSrv_URL + "/payment/get/" + id, CommonResult.class, id);
    }

}

添加feign调用

package com.yg.springcloud.service;

import com.yg.springcloud.entities.CommonResult;
import com.yg.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;

/** * @Author suolong * @Date 2022/6/19 15:06 * @Version 2.0 */
@Component
@FeignClient(value = "cloud-payment-service")
public interface PaymentFeignService { 
        

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

}

6 整体目录结构

7 postman测试：http://localhost/consumer/feign/get/1

• 8001和8002服务器交替出现，说明openfeign自带ribbon负载均衡
• 消费方也打印详细feign调用的日志