com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException：接続が閉じられた後、許可されないオペレーション（JDBCと私のSQLのpingを使用する方法）

Question

MySQLサーバをしようとすると、この下の例外に

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed. 
     at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
     at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) 
     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) 
     at java.lang.reflect.Constructor.newInstance(Unknown Source) 
     at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) 
     at com.mysql.jdbc.Util.getInstance(Util.java:408) 
     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:918) 
     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897) 
     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886) 
     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860) 
     at com.mysql.jdbc.ConnectionImpl.throwConnectionClosedException(ConnectionImpl.java:1187) 
     at com.mysql.jdbc.ConnectionImpl.checkClosed(ConnectionImpl.java:1182) 
     at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4071) 
     at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4040) 
     at com.iseva.Servlet.DS_status_search.doGet(DS_status_search.java:47) 
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) 
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) 
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) 
     at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) 
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) 
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) 
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94) 
     at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) 
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) 
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) 
     at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620) 
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) 
     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:502) 
     at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1104) 
     at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684) 
     at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1519) 
     at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1475) 
     at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) 
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 
     at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) 
     at java.lang.Thread.run(Unknown Source) 
    Nov 30, 2017 2:32:30 PM org.apache.catalina.core.StandardContext reload 
    INFO: Reloading Context with name [/i_seva] has started 
    Nov 30, 2017 2:32:30 PM org.apache.catalina.loader.WebappClassLoaderBase clearReferencesJdbc 
    WARNING: The web application [i_seva] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered. 
    Nov 30, 2017 2:32:30 PM org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads 
    WARNING: The web application [i_seva] appears to have started a thread named [Abandoned connection cleanup thread] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread: 
    java.lang.Object.wait(Native Method) 
    java.lang.ref.ReferenceQueue.remove(Unknown Source) 
    com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:64) 
    java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) 
    java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 
    java.lang.Thread.run(Unknown Source) 
    Nov 30, 2017 2:32:31 PM org.apache.catalina.loader.WebappClassLoaderBase checkStateForResourceLoading 
    INFO: Illegal access: this web application instance has been stopped already. Could not load []. The following stack trace is thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access. 
    java.lang.IllegalStateException: Illegal access: this web application instance has been stopped already. Could not load []. The following stack trace is thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access. 
     at org.apache.catalina.loader.WebappClassLoaderBase.checkStateForResourceLoading(WebappClassLoaderBase.java:1353) 
     at org.apache.catalina.loader.WebappClassLoaderBase.getResource(WebappClassLoaderBase.java:1029) 
     at com.mysql.jdbc.AbandonedConnectionCleanupThread.checkContextClassLoaders(AbandonedConnectionCleanupThread.java:90) 
     at com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:63) 
     at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) 
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 
     at java.lang.Thread.run(Unknown Source) 

    Nov 30, 2017 2:32:32 PM org.apache.jasper.servlet.TldScanner scanJars 
    INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time. 
    Nov 30, 2017 2:32:32 PM org.apache.catalina.core.StandardContext reload 
    INFO: Reloading Context with name [/i_seva] is completed 

を与え続けるです。定期的な間隔でのアクセスデータベースは、私はこの問題を理解しておりませんので、私はそれを検索し、JDBC を使用してPINGを行う方法ping を使用して、それが解決できることを知って来て、私の接続クラスは、この

package Connectionfactory; 

import java.sql.Connection; 
import java.sql.DriverManager; 

public class ConnectionFactory { 


    static Connection cn; 

     static 
     { 

      try{ 

       Class.forName("com.mysql.jdbc.Driver"); 

       } 

      catch(Exception e) 
      { 

       e.printStackTrace(); 
      } 

     } 

     public static Connection getConnection() 
      { 


       try 
       { 
        cn=DriverManager.getConnection("jdbc:mysql://mydb.cn89qwuvudeu.us-east-2.rds.amazonaws.com:3306","XXX","XXXXXXXX"); 
       } 

       catch(Exception p) 

       { 
        p.printStackTrace(); 
       } 




      return cn; 
     } 


} 

のように見えます

これで助けてください上記の方法を追加する必要がありますConnectionFactoryまたはそれを解決する他の方法がありますか？

Answer 1

接続

package Connectionfactory; 

import java.sql.Connection; 
import java.sql.DriverManager; 

public class ConnectionFactory { 
    private Connection cn; 
    public ConnectionFactory() { 
     super(); 
    } 
    public Connection getConnection()throws ClassNotFoundException, SQLException{ 
      Class.forName("com.mysql.jdbc.Driver"); 
      cn=DriverManager.getConnection("jdbc:mysql://mydb.cn89qwuvudeu.us-east-2.rds.amazonaws.com:3306","root","pwd"); 
      return cn; 
    } 
}