以下警告的原因是什么？

WARNING: The web application [TI] 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.

Apr 28, 2016 11:03:25 AM org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads

WARNING: The web application [TI] appears to have started a thread named [MySQL Statement Cancellation Timer] 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.Object.wait(Object.java:503)

java.util.TimerThread.mainLoop(Timer.java:526)

java.util.TimerThread.run(Timer.java:505)

每当我对代码进行更改后,tomcat就会自行重启.

我正在创建mysql连接,我想我正确关闭了它.

这是我的代码.

@RequestMapping(value = "/file/md5", method = RequestMethod.POST)

public ResponseEntity> md5Status(@RequestParam(required = true) String filename) {

Connection con = SqlUtility.getMysqlConnection(host, port, database,username, password);

SqlUtility.closeDbInstances(SqlUtility.mysqlConnection);

SqlUtility.closeDbInstances(con);

return new ResponseEntity<>(HttpStatus.CONFLICT);

}

这是实用程序代码.

public static Connection mysqlConnection = null;

private static PreparedStatement preparedStatement = null;

private static ResultSet resultSet = null;

public static Connection getMysqlConnection(String host, int port, String database, String username,

String password) {

MysqlDataSource mds = null;

try {

if (mysqlConnection == null || mysqlConnection.isClosed()) {

if (database != null && host != null) {

while (mds == null) {

System.out.println("In Loop");

mds = new MysqlDataSource();

mds.setServerName(host);

mds.setPortNumber(port);

mds.setDatabaseName(database);

mds.setUser(username);

mds.setPassword(password);

try {

mysqlConnection = mds.getConnection();

} catch (CommunicationsException e) {

System.out.format(

"Error occurred while trying to get connection with database [%s]. Are your database host [%s] and port [%s] correct? %n%s%n",

database, host, port, e);

mds = null;

// Had to handle for retrying again and again

// This is because your mysql is bind on localhost change it in my.cfg

}

}

} else {

System.out.format(

"Error occurred while trying to get connection with database [%s] with username [%s] and password [%s].

[ATTN] Make sure your DB adapter properties file contains all required attributes. %n",

database, username, password);

}

}

} catch (SQLException e) {

System.out.format(

"Error occurred while trying to get connection at host [%s] with database [%s] with username [%s] and password [%s] %n%s%n",

host, database, username, password, e);

// It might be because of the database privileges which must be grant to access

} catch (RuntimeException e) {

System.out.format("Error occurred while trying to get [%s] Connection %n%s%n", database, e);

}

if (mysqlConnection != null)

System.out.format("[%S] Connection Successfully Created%n", database);

return mysqlConnection;

}

public static void closeDbInstances(Connection con) {

System.out.println("Trying to close Database Connection...");

if (con != null && preparedStatement != null && resultSet != null) {

try {

resultSet.close();

preparedStatement.close();

con.close();

System.out.println("Database Connection Closed");

} catch (SQLException e) {

System.out.println("Error occurred while trying to close Database connection " + e);

}

}

}