前置知識:nacos已經跑起來;

建立簡單案例如下,首先建立maven專案,結構:

pom.xml:

<?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">
    <modelVersion>4.0
 
.0</modelVersion>

    <groupId>com.jingzhe</groupId>
    <artifactId>configdemo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <!-- 父依賴均是springboot-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3
 
.2.RELEASE</version>
    </parent>

    <dependencies>
        <!--nacos配置相關;版本會引入springcloud alibaba當中的版本,也就是2.2.5.RELEASE-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <!--其中,scope和type是有必要的,否則maven會報錯哦-->
        <dependencies>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.2
 
.5.RELEASE</version>
                <scope>import</scope>
                <type>pom</type>
            </dependency>
        </dependencies>
    </dependencyManagement>

</project>

ConfigDemoApplication.java:

package com.jingzhe;

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

/**
 * @author: Xu Xiang  @createTime: 2021/6/26 18:06
 * Description: 
 */
@SpringBootApplication
public class ConfigDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(ConfigDemoApplication.class);
    }
}

TestController.java:

package com.jingzhe;

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;

/**
 * @author: Xu Xiang  @createTime: 2021/6/26 18:08
 * Description:
 *  1.RefreshScope(org.springframework.cloud.context.scope.refresh)是spring cloud提供的一種特殊的scope實現，用來實現配置、例項熱載入;
 */
@RestController
@RefreshScope
public class TestController {
    @Value("${testStr}")
    private String testStr;

    @GetMapping("/test")
    public String test() {
        return testStr;
    }
}

注意看註釋;

bootstrap.yaml:

#bootstrap.yaml檔案一般,用來儲存最先啟動的配置變數
#其中spring.application.name要和nacos配置中心的dataId是一致的
spring:
  application:
    name: configdemo
  cloud:
    nacos:
      config:
        server-addr: localhost:8848
        file-extension: yaml

啟動nacos:

之後,啟動專案,訪問:localhost:8080/test:

以上；