Nacos 配置中心：动态加载 Bean

前提：已经集成好 springboot / cloud 与nacos的环境

1 nacos中配置文件参数

message:
  #sender: emailMessageSender
  sender: smsMessageSender

2 接口和两个实现类

public interface MessageSender {
    String sendMessage(String message, String recipient);
}


import org.springframework.stereotype.Service;
@Service("emailMessageSender")
public class EmailMessageSender implements MessageSender {
    @Override
    public String sendMessage(String message, String recipient) {
        StringBuilder append = new StringBuilder().append("邮件发送成功，收信人：").append(recipient).append("，邮件内容：").append(message);
        return append.toString();
        // 实际的邮件发送逻辑...
    }
}


import org.springframework.stereotype.Service;
@Service("smsMessageSender")
public class SmsMessageSender implements MessageSender {
    @Override
    public String sendMessage(String message, String recipient) {
        StringBuilder append = new StringBuilder().append("短信发送成功，短信内容：").append(message).append("，接收人：").append(recipient);
        return append.toString();
        // 实际的短信发送逻辑...
    }
}

3 动态bean切换配置，注意@RefreshScope，有两处

import org.springframework.beans.BeansException;
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.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@RefreshScope
public class MessageSenderConfig {

    @Autowired
    private ApplicationContext applicationContext;

    @Value("${message.sender}")
    private String messageSenderBeanName;

    @Bean
    @RefreshScope
    public MessageSender messageSender() {
        // 根据Nacos配置动态获取对应的Bean
        try {
            return (MessageSender) applicationContext.getBean(messageSenderBeanName);
        } catch (BeansException e) {
            throw new RuntimeException("未找到对应的处理器");
        }
    }
}

4 controller层调用

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;


@RestController
@RequestMapping("/notification")
public class Controller_Notification {

    @Autowired
    private MessageSender messageSender;

    @RequestMapping("/sendNotification")
    public String sendNotification(String message, String recipient)
    {
        String s = messageSender.sendMessage(message, recipient);
        return s;
    }

}