tomcat服务器宕机解决方案

package cn.listener;

import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Enumeration;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

import com.mysql.jdbc.AbandonedConnectionCleanupThread;


@WebListener
public class ContextFinalizer implements ServletContextListener {

    public void contextInitialized(ServletContextEvent sce) {
    }

    public void contextDestroyed(ServletContextEvent sce) {
        Enumeration<Driver> drivers = DriverManager.getDrivers();
        Driver d = null;
        while (drivers.hasMoreElements()) {
            try {
                d = drivers.nextElement();
                DriverManager.deregisterDriver(d);
                System.out.println(String.format("ContextFinalizer:Driver %s deregistered", d));
            } catch (SQLException ex) {
                System.out.println(String.format("ContextFinalizer:Error deregistering driver %s", d) + ":" + ex);
            }
        }
        try {
            AbandonedConnectionCleanupThread.shutdown();
        } catch (InterruptedException e) {
            System.out.println("ContextFinalizer:SEVERE problem cleaning up: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

  <listener>
    <listener-class>cn.listener.ContextFinalizer</listener-class>
  </listener>