轻松入门Nacos（轻松入门 iphone）

1. 安装nacos，这里采用docker安装，不清楚docker，请移步centos8.0 docker演示

1) 拉取最新版本nacos

docker pull nacos/nacos-server

2) 查看镜像

docker images

3) 启动nacos，这里做了端口映射，映射为8080

docker run --env MODE=standalone --name nacos -d -p 8080:8848 nacos/nacos-server

4) 访问nacos，默认用户名和密码均为nacos，http://127.0.0.1:8080/nacos/#/login

2. 测试服务注册于发现

1) 创建maven父项目nacos-test，删除src目录

2) 引入POM依赖

   <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.4.RELEASE</version>
        <relativePath/>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--服务注册与发现-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2.2.0.RELEASE</version>
        </dependency>
        <!--配置中心-->
        <dependency>
            groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            <version>2.2.0.RELEASE</version>
        </dependency>
        <!--feign调用，RPC通讯,集成ribbon辅助均衡-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>2.2.1.RELEASE</version>
        </dependency>
    </dependencies>

3) 创建生产者

A. 在父项目nacos-test下创建module，此处命名为nacos-service

B. 创建启动类NacosServiceApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

C. 创建配置文件bootstrap.yml，因为加载顺序的问题，此处必须是bootstrap.yml，而不是application.yml，否则引入了nacos config会启动失败

server:
  port: 8091

 spring:
  application:
    #定义服务名
    name: nacos-service
  cloud
    nacos:
      discovery:
        #注册中心地址
        server-addr: http://127.0.0.1:8080
      config:
        #配置中心地址
        server-addr: http://127.0.0.1:8080
        #组别
        group: DEFAULT_GROUP
        #文件类别
        file-extension: yaml
  #使用环境
  profiles:
    active: dev

D. 创建类NacosService.java提供服务

import com.alex.nacosconfigfile.ProducerConfigInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class NacosService {
    @Value("${server.port}")
    private String serverPort;
 
    @Autowired
    private ProducerConfigInfo producerConfigInfo;
  
    @GetMapping("/sayHello")
    @RefreshScope
    public String sayHello(){
        return "我是生产者，我的端口号为："+serverPort+"，nacos-config配置内容为："+producerConfigInfo.getProducerContent();
    }
}

E. 创建配置文件ProducerConfigInfo.java类，用于测试nacos config

import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Configuration;

 
@Configuration
@RefreshScope
public class ProducerConfigInfo {

    @Value("${producer.content}")
    private String producerContent;

    public String getProducerContent() {
        return producerContent;
    }

    public void setProducerContent(String producerContent) {
        this.producerContent = producerContent;
    }
}

F. 在控制台创建配置文件nacos-service-dev.yaml

G. 分别用8091和8092两个端口启动生产者项目，创建集群，以便验证负载均衡，查看nacos服务列表是否注册成功

4) 创建消费者

A. 在父项目nacos-test下创建module，此处命名为nacos-customer

B. 创建启动类NacosCustomerApplication.java

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

@SpringBootApplication
/***开启openfeign客户端*/
@EnableFeignClients
public class NacosCustomerApplication {
    public static void main(String[] args) {
        SpringApplication.run(NacosCustomerApplication.class,args);
    }

}

C. 创建配置文件bootstrap.yml,因为是在父pom中引入的依赖，只要引入了nacos config的依赖，配置文件名称都必须是bootstrap.yml，且必须配置nacos config相关信息，否则启动失败

server:
  port: 9001

spring:
  application:
    #定义服务名
    name: nacos-customer
  cloud:
    nacos:
      discovery:
        #注册中心地址
        server-addr: http://127.0.0.1:8080
      config:
        #配置中心地址
        server-addr: http://127.0.0.1:8080
        #组别
        group: DEFAULT_GROUP
        #文件类别
        file-extension: yaml

D. 创建openfeign客户端，NacosServiceFeign.java

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;

@FeignClient("nacos-service")
public interface NacosServiceFeign {
    @GetMapping("sayHello")
    String sayHello();
}

E. 创建消费者NacosCustomerService.java调用生产者接口

import com.alex.feign.NacosServiceFeign;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class NacosCustomerService {
    @Autowired
    private NacosServiceFeign nacosServiceFeign;
 
    @GetMapping("/getTestResult")
    public String getTestResult() {
        String result = nacosServiceFeign.sayHello();
        return "我是消费者，通过ribbon负载均衡调用sevice返回结果:" + result;
    }
}

F. 启动消费者，并调用http://127.0.0.1:9001/getTestResult

动态均衡演示：

动态配置修改演示，修改配置文件值为2222，旧值为1111,如图：