我有以下问题。我正在服务器上编写带有数据库的桌面java应用程序。我也使用hibernate。当我运行应用程序时，一切正常，我与数据库的连接正确，但几分钟后我在数据库上执行某些操作时出现以下错误：
app.form.register:
class: Symfony\Component\Form\Form
arguments: [@FormConfigInterface]
这是我的hibernate.cfg.xml文件：
Exception thrown:
Class: model.MainRepository
Stack Trace:
org.hibernate.TransactionException: JDBC begin transaction failed:
at org.hibernate.resource.jdbc.internal.AbstractLogicalConnectionImplementor.begin(AbstractLogicalConnectionImplementor.java:72)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:238)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:213)
at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:52)
at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1443)
at model.MainRepository.addTrainingToUser(MainRepository.java:151)
at model.Parser.parseFilesWatch(Parser.java:85)
at controller.UploadDataController$1.call(UploadDataController.java:148)
at javafx.concurrent.Task$TaskCallable.call(Task.java:1423)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
Last packet sent to the server was 11 ms ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2985)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2871)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3414)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2536)
at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:4874)
at org.hibernate.resource.jdbc.internal.AbstractLogicalConnectionImplementor.begin(AbstractLogicalConnectionImplementor.java:67)
... 10 more
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2431)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2882)
... 17 more
Exception thrown:
Class: model.MainRepository
Stack Trace:
org.hibernate.TransactionException: JDBC begin transaction failed:
at org.hibernate.resource.jdbc.internal.AbstractLogicalConnectionImplementor.begin(AbstractLogicalConnectionImplementor.java:72)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:238)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:213)
at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:52)
at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1443)
at model.MainRepository.sendTrainingDetails(MainRepository.java:184)
at model.Parser.parseFilesWatch(Parser.java:94)
at controller.UploadDataController$1.call(UploadDataController.java:148)
at javafx.concurrent.Task$TaskCallable.call(Task.java:1423)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Connection.close() has already been called. Invalid operation in this state.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:984)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926)
at com.mysql.jdbc.ConnectionImpl.getMutex(ConnectionImpl.java:3018)
at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:4827)
at org.hibernate.resource.jdbc.internal.AbstractLogicalConnectionImplementor.begin(AbstractLogicalConnectionImplementor.java:67)
... 10 more
HibernateUtil.java
<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="connection.pool_size">1</property>
<property name="hibernate.connection.url">jdbc:mysql://sql.aaa.nazwa.pl:1111/aaaa</property>
<property name="hibernate.connection.username">aaa</property>
<property name="hibernate.connection.password">bbb</property>
<property name="show_sql">true</property>
<mapping resource="model/models.hbm.xml"/>
</session-factory>
</hibernate-configuration>
对数据库进行示例操作：
package model;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
/**
* Created by Piotr on 2015-10-11.
*/
public class HibernateUtil {
private static final SessionFactory sessionFactory = buildSessionFactory();
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from hibernate.cfg.xml
return new Configuration().configure().buildSessionFactory();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
public static void shutdown() {
// Close caches and connection pools
getSessionFactory().close();
}
}
答案 0 :(得分：1)
好的，我已经解决了这个问题。参数叫做＆＃39; idleConnectionTestPeriod＆＃39;在c3p0中应该设置。来自文档"If this is a number greater than 0, c3p0 will test all idle, pooled but unchecked-out connections, every this number of seconds."
答案 1 :(得分：0)
这很可能是因为使用内置的Hibernate连接池currently unsupported as specified in the documentation而且你设置的大小为1。