前言

记录下SpringBoot修改yml配置文件后无需重启服务的方式（打包后生效），效果如下：
在这里插入图片描述

具体实现

实现代码

pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
</dependencies>

application.yml

#端口号
server:
  port: 31091

spring:
  profiles:
    active: dev

application-dev.yml

coisini:
    mail: maggieq8324@gmail.com

InitializationConfig.java

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
import java.util.Map;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * @Description spring容器初始化完成后进行一些其他初始化操作
 * @date Mar 24, 2022
 * @version 1.0
 */
@Slf4j
@Component
public class InitializationConfig implements ApplicationRunner {

    private static ScheduledExecutorService executorService = Executors.newScheduledThreadPool(1);
    private static String profile;

    @Override
    public void run(ApplicationArguments applicationArguments) throws Exception {
        scheduleUpdateConf();
    }

    private void scheduleUpdateConf() {
        try {
            Map lhm = YmlUtil.loadYaml("application.yml");
            profile = (String) YmlUtil.getValByKey(lhm, "spring.profiles.active");
        } catch (Exception e) {
            log.error("加载配置文件application.yml异常");
        }

        // TODO 开启定时刷新内存中配置文件内容
        log.info("refresh config file start");
        executorService.scheduleAtFixedRate(InitializationConfig::updateConfVal, 0, 10, TimeUnit.SECONDS);
        log.info("refresh config file end");
    }

    /**
     * 更新配置文件值
     */
    private static void updateConfVal(){
        try{
            Map lhm = YmlUtil.loadYaml("application-" + profile + ".yml");

            String mail = YmlUtil.getValByKey(lhm,"coisini.mail").toString();
            DynamicMailConfig instance = DynamicMailConfig.getInstance();
            if (!instance.getDynamicMail().equals(mail)) {
                instance.setDynamicMail(mail);
                log.info("实时配置mail更新：" + instance.getDynamicMail());
            }
        } catch (Exception e){
            log.error("更新配置文件值异常: ", e);
        }
    }

}

DynamicMailConfig.java

/**
 * @Description 动态邮箱单例
 * @date Mar 24, 2022
 * @version 1.0
 */
public class DynamicMailConfig {

    private static String mail;

    private final static DynamicMailConfig dynamic;

    static {
        dynamic = new DynamicMailConfig();
    }

    private DynamicMailConfig() {
        mail = "";
    }

    public static DynamicMailConfig getInstance() {
        return dynamic;
    }

    public String getDynamicMail() {
        return mail;
    }

    public void setDynamicMail(String mail) {
        this.mail = mail;
    }

}

YmlUtil.java

import org.yaml.snakeyaml.Yaml;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * @Description 动态操作yml配置文件工具类
 *  【需要将config配置文件夹和项目jar包放在同级别目录下，这样修改config下的配置文件后，jvm才能及时得获取新的配置】
 * @date Mar 24, 2022
 * @version 1.0
 */
public class YmlUtil {

    public static LinkedHashMap loadYaml(String fileName) throws Exception{
        String path = System.getProperty("user.dir");

        File file = new File(path + "/config/" + fileName);
        InputStream in;
        if (file.exists()) {
            in = new FileInputStream(path + "/config/" + fileName);
        } else {
            // TODO 如果没有config文件夹，则从项目的resources目录下找
            in = YmlUtil.class.getClassLoader().getResourceAsStream(fileName);
        }

        LinkedHashMap lhm = new Yaml().loadAs(in, LinkedHashMap.class);
        return lhm;
    }

    public static Object getValByKey(Map lhm, String key) throws Exception{
        String[] keys = key.split("[.]");
        Map ymlInfo = lhm;
        for (int i = 0; i < keys.length; i++) {
            Object value = ymlInfo.get(keys[i]);
            if (i < keys.length - 1) {
                ymlInfo = (Map) value;
            } else if (value == null) {
                throw new Exception("key不存在");
            } else {
                return value;
            }
        }

        return null;
    }

}

测试

TestController.java

@Slf4j
@RestController
public class TestController {

    @GetMapping("/getDynamicMail")
    public String getDynamicMail() {
        String dynamicMail = DynamicMailConfig.getInstance().getDynamicMail();
        log.info("getDynamicMail: " + dynamicMail);
        return dynamicMail;
    }
    
}