SpringBoot Nacos 安装、注解开发配置自动加载更新并监听

SpringBoot Nacos 安装及配置入门Demo

基于注解

• 安装

1. 下载tar包

github https://github.com/alibaba/nacos/releases/tag/1.4.0 不过下载的有时候很慢

csdn https://download.csdn.net/download/HumorChen99/13344131 我发的，免费下

2. 解压即可，在bin目录有startup.sh启动

#进入bin目录并以独立模式启动
./startup.sh -m standalone

3. 在浏览器访问 http://ip:8848/nacos 账号密码默认都为nacos
4. 添加一个测试配置 systemSwtich值设置为true

• 建立springboot项目

• 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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <parent>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-parent</artifactId>
          <version>2.2.2.RELEASE</version>
          <relativePath/> <!-- lookup parent from repository -->
      </parent>
      <groupId>com.example</groupId>
      <artifactId>springboot_nacos_demo</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <name>springboot_nacos_demo</name>
      <description>Demo project for Spring Boot</description>
  
      <properties>
          <java.version>1.8</java.version>
      </properties>
  
      <dependencies>
          <dependency>
              <groupId>com.alibaba.boot</groupId>
              <artifactId>nacos-config-spring-boot-starter</artifactId>
              <version>0.2.7</version>
          </dependency>
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-web</artifactId>
          </dependency>
  
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-devtools</artifactId>
              <scope>runtime</scope>
              <optional>true</optional>
          </dependency>
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-configuration-processor</artifactId>
              <optional>true</optional>
          </dependency>
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-test</artifactId>
              <scope>test</scope>
          </dependency>
      </dependencies>
  
      <build>
          <plugins>
              <plugin>
                  <groupId>org.springframework.boot</groupId>
                  <artifactId>spring-boot-maven-plugin</artifactId>
              </plugin>
          </plugins>
      </build>
  
  </project>
  
  

• application.yml

  nacos:
    config:
      server-addr: 192.168.108.129:8848
  server:
    port: 80
  

• controller代码

autoRefreshed参数为是否自动刷新，开启后一旦配置更新即可同步更新
NacosValue(value = “${systemSwitch:false}”,autoRefreshed = true)
systemSwitch:false 配置:默认值，也就是查不到的时候返回这个默认的

  package com.example.springboot_nacos_demo.controller;
  
  import com.alibaba.nacos.api.config.ConfigType;
  import com.alibaba.nacos.api.config.annotation.NacosValue;
  import com.alibaba.nacos.spring.context.annotation.config.NacosPropertySource;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;
  
  @RestController
  @RequestMapping("/nacos")
  @NacosPropertySource(dataId = "example",autoRefreshed = true)
  public class NacosController {
      @NacosValue(value = "${systemSwitch:false}",autoRefreshed = true)
      private boolean systemSwitch;
  
      @GetMapping("/systemSwitch")
      public boolean getSystemSwitch(){
          return this.systemSwitch;
      }
  }

• 浏览器打开查看内容
  

• 监听配置更新事件 @NacosConfigListener(dataId = “example”)

type为配置类型，可以为properties yaml json等等
一旦配置变更，该方法将收到消息，做自定义处理

  @RestController
  @RequestMapping("/nacos")
  @NacosPropertySource(dataId = "example",autoRefreshed = true,type = ConfigType.JSON)
  public class NacosController {
      @NacosValue(value = "${systemSwitch:false}",autoRefreshed = true)
      private boolean systemSwitch;
  
      @NacosConfigListener(dataId = "example")
      public void onMessage(String msg){
          System.out.println(msg);
      }
      
      @GetMapping("/systemSwitch")
      public boolean getSystemSwitch(){
          return this.systemSwitch;
      }
  }

一旦配置被更改，监听的接口将立即收到消息。在示范里我们打印了传来的消息，是更新后的配置

• 访问 http://localhost/nacos/systemSwitch显示true