springboot项目中整合Lislietener。动态获取数据

listener监听事件

package listener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
import java.util.concurrent.atomic.AtomicInteger;


/**
 * 监听在线人数
 * @author xuemeng
 * @date 2019/5/9 14:53
 */
public class MySessionListener implements HttpSessionListener {
        //初始在线人数为0
        public static AtomicInteger userCount = new AtomicInteger(0);

        /**
         * 用户登录,创建session会话，获得当前用户登录数+1
         * @param httpSessionEvent
         */
        @Override
        public void sessionCreated(HttpSessionEvent httpSessionEvent) {
                userCount.getAndIncrement();
        }
        /**
         * 用户退出,创建session会话，获得当前用户登录数-1
         * @param httpSessionEvent
         */
        @Override
        public void sessionDestroyed(HttpSessionEvent httpSessionEvent) {
                userCount.getAndDecrement();
        }
}

监听事件注册

package config;


import com.gsww.iscs.apis.listener.MySessionListener;
import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;


/**
 * @author xuemeng
 * @date 2019/5/9 15:04
 */
@Configuration
public class SpringMvcConfig implements WebMvcConfigurer {
        @Bean
        public ServletListenerRegistrationBean getListener() {
                ServletListenerRegistrationBean servletListenerRegistrationBean = new ServletListenerRegistrationBean();
                servletListenerRegistrationBean.setListener(new MySessionListener());                            return servletListenerRegistrationBean;
        }

}

获取监听到得到数据

@Override
public int getOnLineUser() {
        int count=0;
        //获取session
        AtomicInteger userCount = MySessionListener.userCount;
        count=(Integer.parseInt(userCount+""));
        return count;
}

*注意：一定是web项目，需要在pom中引入web包