1、读取nacos配置类Config.java

package com.northking.system.controller.system;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.stereotype.Component;

@Component
@RefreshScope
public class Config {
    // 这里使用到的是ConfigurableApplicationContext 来获取配置中心到值。
    @Autowired
    private ConfigurableApplicationContext configurableApplicationContext;
    //这个变量最好和nacos里需要获取到一致。方便识别
    public String driver;
    public String url;
    public String usernames;
    public String passwords;

    //get和set方法
    public void setDriver(String driver) {
        this.driver = driver;
    }
    //get方法处理一下
    public String getDriver() {
        //这里的xx.xx是你配置中心要获取到值
        /*例如你的nacos需要获取的是这样到
         *monthTime:
         *  maxloglength: 9000
         * 那么这个地方就是monthTime.maxloglength
         */
        return driver = configurableApplicationContext.getEnvironment().getProperty("driver");
    }

    public void setUrl(String url) {
        this.url = url;
    }
    public String getUrl() {

        return url = configurableApplicationContext.getEnvironment().getProperty("url");
    }

    public void setUsernames(String usernames) {
        this.usernames = usernames;
    }
    public String getUsernames() {

        return usernames = configurableApplicationContext.getEnvironment().getProperty("usernames");
    }

    public void setPasswords(String passwords) {
        this.passwords = passwords;
    }
    public String getPasswords() {

        return passwords = configurableApplicationContext.getEnvironment().getProperty("passwords");
    }
}

2、编写SpringContextUtil.java

package com.northking.system.controller.system;

import org.springframework.beans.BeansException;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
@RefreshScope
public class SpringContextUtil implements ApplicationContextAware {
    private static ApplicationContext applicationContext = null;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if (SpringContextUtil.applicationContext == null) {
            SpringContextUtil.applicationContext = applicationContext;
        }
    }
    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    public static Object getBean(String maxloglength) {

        return getApplicationContext().getBean(maxloglength);
    }

    public static <T> T getBean(Class<T> clazz) {
        T test=getApplicationContext().getBean(clazz);
        return test;
    }

    public static <T> T getBean(String maxloglength, Class<T> clazz) {
        return getApplicationContext().getBean(maxloglength, clazz);
    }
}

3、测试类

package com.northking.system.controller.system;

import org.springframework.beans.factory.annotation.Value;

import javax.annotation.PostConstruct;

public class TestController {
    public static void testNaocs(){
        Config config= SpringContextUtil.getBean(Config.class);
        //这个len就是根据你nacos动态获取的值。完成
        String driver=config.getDriver();
        String url=config.getUrl();
        String usernames=config.getUsernames();
        String passwords=config.getPasswords();
    }
}

也可以用在静态属性

public class Demo {
    public static final String URL;
    static {
    		Config property = SpringContextUtil.getBean(Config.class);
    		URL = property.getUrl();
    } 
}