Соединение с MySQL: Ошибка связи связи

Question

Я хочу запустить свою программу на внешнем компьютере. Первое подключение к базе данных работает нормально, но как только первый запрос отправляется на базу данных, я получаю эту ошибку:

Nov 18, 2013 10:55:24 AM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions 
WARN: SQL Error: 0, SQLState: 08S01 
Nov 18, 2013 10:55:24 AM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions 
ERROR: Communications link failure 

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. 
org.hibernate.exception.JDBCConnectionException: Could not open connection 
    at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:132) 
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49) 
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125) 
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110) 
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:221) 
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:157) 
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67) 
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160) 
    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1432) 
    at de.util.HibernateUtil.getList(HibernateUtil.java:230) 
    at de.commands.login.LoginCommand.executeServer(LoginCommand.java:35) 
    at de.commands.login.LoginCommand.executeServer(LoginCommand.java:20) 
    at de.commands.SessionManager.execute(SessionManager.java:142) 
    at de.commands.SessionManager.execute(SessionManager.java:124) 
    at de.commands.CommandExecutionThread.run(CommandExecutionThread.java:27) 
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure 

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:525) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) 
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121) 
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:357) 
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2482) 
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2519) 
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2304) 
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834) 
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:525) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) 
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416) 
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346) 
    at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.getConnection(DriverManagerConnectionProviderImpl.java:204) 
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:292) 
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:214) 
    ... 10 more 
Caused by: java.net.ConnectException: Connection refused 
    at java.net.PlainSocketImpl.socketConnect(Native Method) 
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) 
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) 
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) 
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391) 
    at java.net.Socket.connect(Socket.java:579) 
    at java.net.Socket.connect(Socket.java:528) 
    at java.net.Socket.<init>(Socket.java:425) 
    at java.net.Socket.<init>(Socket.java:241) 
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:259) 
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:307) 
    ... 25 more 

полистав другие потоки, другие люди были проблемы с тайм-аутом. Мои проблемы кажутся разными, поскольку он говорит, что последний полученный пакет был 0 мс назад. Кроме того, работа с phpmyadmin никогда не вызывала никаких проблем. Тем не менее, мои значения времени ожидания являются:

connect_timeout: 10 
interactive_timeout: 28800 
wait_timeout: 28800 

Edit:

Вот мой спящий режим конфигурации:

<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 
<hibernate-configuration> 
    <session-factory> 
     <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> 
     <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> 
     <property name="hibernate.connection.url">jdbc:mysql://localhost/ws?autoReconnect=true&user=user&password=pw</property> 
     [...] 
    </session-factory> 
</hibernate-configuration> 

Метод, в котором доступ к базе:

public static <T> List<T> getList(DetachedCriteria criteria) 
{ 
    SessionFactory sf = HibernateUtil.getSessionFactory(); 
    Session session = null; 
    List<T> l = new LinkedList<>(); 

    try 
    { 
     session = sf.openSession(); 
     session.beginTransaction(); // This is the line where the exception occurs 
     List list = criteria.getExecutableCriteria(session).list(); 
     for (Object o : list) 
     { 
      l.add((T) o); 
     } 
     session.getTransaction().commit(); 
    } catch (HibernateException he) 
    { 
     he.printStackTrace(); 
    } finally 
    { 
     session.close(); 
    } 

    return l; 
} 

Answer 1

Yust make shure youre ссылка JDBC верна, il привести пример:

Он должен выглядеть следующим образом:

return conn = DriverManager.getConnection("jdbc:mysql://"+IP+"/"+DB, User, Pass); 

сделать Youre собственную базу данных и использовать Youre информацию по ссылке JDBC:

//DB: exampledb 
//Database username: exampleusername 
//Pass: examplepassword 


return conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/exampledb","exampleusername", "examplepassword"); 

порты необходимы для подключения к MySQL. (вы можете выбрать 127.0.0.1:3306 или localhost: 3306). Они оба одинаковы.

Надеялся, это помогло вам.