1. 引入方式

　　import  static  类路径.*;

2. 示例

2.1 需要被导入的类

package com.streamax.s17.mcs.business.message;import javax.annotation.Resource;import java.util.Date;import java.util.Map;/** * @Describe: * @Author: chenfan * @Date: 2019/4/29 13:26 */@Slf4j@Componentpublic class MqttMessageListener implements IMqttMessageListener {    public static final String TRANSFER_BEGIN = "s17/media/handout/op_session_client_pull_begin";    public static final String TRANSFER_END = "s17/media/handout/op_session_client_pull_end";    public static final String TRANSFER_CONTROL = "s17/media/op_session_control";}

2.2 需要导入的类

package com.streamax.s17.mcs.business.message;import lombok.extern.slf4j.Slf4j;import org.eclipse.paho.client.mqttv3.MqttClient;import org.eclipse.paho.client.mqttv3.MqttException;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;import static com.streamax.s17.mcs.business.message.MqttMessageListener.*;/** * @Describe: * @Author: chenfan * @Date: 2019/4/26 15:17 */@Slf4j@Componentpublic class MessageHandler {    private MqttMessageListener listener;    private MqttClient mqttClient;    public static final String filter = "/#";    @Autowired    public MessageHandler(MqttClient mqttClient,MqttMessageListener listener ) {        this.mqttClient = mqttClient;        this.listener = listener;        init();    }    /**     * 订阅关心事件     */    public void init(){        try {
    　　　　　　　// 导入后即可通过变量名直接使用，不需要通过类名引用变量            mqttClient.subscribe(TRANSFER_BEGIN + filter, 1, listener);            mqttClient.subscribe(TRANSFER_END + filter, 1, listener);            mqttClient.subscribe(TRANSFER_CONTROL + filter, 1, listener);            log.info("subscribe topics success");        } catch (MqttException e) {            log.error("subscribe topics occur a exception:{ }",e);        }    }}