org.hibernate.exception.JDBCConnectionException：无法打开连接时打开transcation

我与Hibernate，Java和MySQL和一个多线程应用程序wotking，有时下面的异常抛出当我试图打开一个交易。org.hibernate.exception.JDBCConnectionException：无法打开连接时打开transcation

HibernateUtils.java

@ImportResource("classpath:application.properties") 
public class HibernateUtil { 

    private static volatile SessionFactory INSTANCE_SESSION_FACTORY = null; 

    public enum Common { 
     SUCCESS, ROLLBACK 
    } 

    private synchronized static void createSessionFactory() { 
     try { 
      if (INSTANCE_SESSION_FACTORY != null) { 
       return; 
      } 
      ResourceBundle rb = ResourceBundle.getBundle("application"); 
      Integer environment = Integer.valueOf(rb.getString("environment")); 

      Properties prop = new Properties(); 

      switch (environment) { 
      /* LOCAL */ 
      case 1: 
       prop.setProperty("hibernate.connection.driver_class", rb.getString("hibernate.driver.class.name")); 
       prop.setProperty("hibernate.connection.url", rb.getString("hibernate.db.uri")); 
       prop.setProperty("hibernate.connection.username", rb.getString("hibernate.db.username")); 
       prop.setProperty("hibernate.connection.password", rb.getString("hibernate.db.password")); 
       break; 

      default: 
       throw new ConfigurationException(environment == null ? "No environment added in application.properties" 
         : "Wrong environment added in application.properties"); 
      } 

      prop.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect"); 
      prop.setProperty("hibernate.show_sql", "true"); 
      prop.setProperty("hibernate.hbm2ddl.auto", "update"); 
      prop.setProperty("hibernate.current_session_context_class", "thread"); 
      prop.setProperty("hibernate.connection.charSet", "UTF-8"); 
      prop.setProperty("hibernate.ejb.naming_strategy", "org.hibernate.cfg.ImprovedNamingStrategy"); 
      prop.setProperty("hibernate.connection.pool_size", "10"); 

      prop.setProperty("hibernate.c3p0.minPoolSize", "1"); 
      prop.setProperty("hibernate.c3p0.maxPoolSize", "3"); 
      prop.setProperty("hibernate.c3p0.initialPoolSize", "1"); 
      prop.setProperty("hibernate.c3p0.timeout", "1800"); 
      prop.setProperty("hibernate.c3p0.max_statements=", "50"); 

      org.hibernate.cfg.Configuration config = new org.hibernate.cfg.Configuration().addProperties(prop) 
        .addAnnotatedClass(Account.class).addAnnotatedClass(InsynctiveProperty.class) 
        .addAnnotatedClass(CrossBrowserAccount.class).addAnnotatedClass(EmergencyContact.class) 
        .addAnnotatedClass(USAddress.class).addAnnotatedClass(CreatePersonForm.class) 
        .addAnnotatedClass(ParamObject.class).addAnnotatedClass(Test.class); 

      ServiceRegistryBuilder builder = new ServiceRegistryBuilder().applySettings(config.getProperties()); 
      INSTANCE_SESSION_FACTORY = config.buildSessionFactory(builder.buildServiceRegistry()); 
     } catch (Throwable ex) { 
      System.err.println("Initial SessionFactory creation failed." + ex); 
      throw new ExceptionInInitializerError(ex); 
     } 
    } 

    public synchronized static SessionFactory getSessionFactory() { 
     if (INSTANCE_SESSION_FACTORY == null) { 
      createSessionFactory(); 
     } 
     return INSTANCE_SESSION_FACTORY; 
    } 

    public static final ThreadLocal<Session> session = new ThreadLocal<Session>(); 

     public static Session getCurrentSession() { 
      try{ 
       Session session = getSessionFactory().getCurrentSession(); 
       System.out.println("The session was opened."); 
       return session; 
      } catch(Exception ex){ 
       ex.fillInStackTrace(); 
       System.out.println("Problems on Open the session."); 
       throw ex; 
      } 
     } 

     public static void closeSession(Session session) { 
//   try{ 
//    session.close(); 
//    System.out.println("The Session is close."); 
//   } catch(Exception ex){ 
//    ex.fillInStackTrace(); 
//    System.out.println("Problems on clossing the session."); 
//    throw ex; 
//   } 
     } 

    public static Object get(Class<?> clazz, Integer id) { 
     Session session = getCurrentSession(); 
     Transaction transaction = null; 
     Object obj = null; 
     try { 
      transaction = openTransaction(session); 
      obj = session.get(clazz, id); 
      transaction.commit(); 
      return obj; 
     } catch (RuntimeException ex) { 
      if (transaction != null) { 
       transaction.rollback(); 
      } 
      ex.printStackTrace(); 
      throw ex; 
     } finally { 
      closeSession(session); 
     } 
    } 

    public Common save(Object object) { 
     Session session = getCurrentSession(); 
     Transaction transaction = null; 
     Common result = null; 
     try { 
      transaction = openTransaction(session); 
      session.save(object); 
      transaction.commit(); 
      result = Common.SUCCESS; 
     } catch (Exception e) { 
      e.printStackTrace(); 
      if (transaction != null) { 
       transaction.rollback(); 
      } 
      result = Common.ROLLBACK; 
     } finally { 
      closeSession(session); 
     } 

     return result; 
    } 

    public Common update(Object object) { 
     Session session = getCurrentSession(); 
     Transaction transaction = null; 
     Common result; 

     try { 
      transaction = openTransaction(session); 
      session.update(object); 
      transaction.commit(); 
      result = Common.SUCCESS; 
     } catch (Exception e) { 
      e.printStackTrace(); 

      if (transaction != null) { 
       transaction.rollback(); 
      } 
      result = Common.ROLLBACK; 
     } finally { 
      closeSession(session); 
     } 
     return result; 
    } 

    public static Transaction openTransaction(Session session) { 
     try { 
      return session.beginTransaction(); 
     } catch(Exception ex){ 
      ex.printStackTrace(); 
      throw ex; 
     } 
    } 
}

堆栈跟踪

org.hibernate.exception.JDBCConnectionException: Could not open connection 
    at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:131) 
    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:304) 
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:169) 
    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:1396) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:483) 
    at org.hibernate.context.internal.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:352) 
    at com.sun.proxy.$Proxy66.beginTransaction(Unknown Source) 
    at insynctive.utils.HibernateUtil.openTransaction(HibernateUtil.java:201) 
    at insynctive.utils.HibernateUtil.get(HibernateUtil.java:139) 
    at insynctive.tests.TestMachine.changeParamObject(TestMachine.java:368) 
    at insynctive.tests.LoadingTests.hrPeopleLoadingTest(LoadingTests.java:72) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:483) 
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:85) 
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:659) 
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:845) 
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1153) 
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125) 
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:108) 
    at org.testng.TestRunner.privateRun(TestRunner.java:771) 
    at org.testng.TestRunner.run(TestRunner.java:621) 
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:357) 
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:352) 
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:310) 
    at org.testng.SuiteRunner.run(SuiteRunner.java:259) 
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52) 
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86) 
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1199) 
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1124) 
    at org.testng.TestNG.run(TestNG.java:1032) 
    at insynctive.runnable.RunnableTest.run(RunnableTest.java:36) 
    at java.lang.Thread.run(Thread.java:745) 
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

打开连接，有时会出现这种错误。为什么？

来源

2015-11-11 Eugenio Valeiras

可能重复：http://stackoverflow.com/questions/6865538/solving-a-communications-link-failure-with-jdbc-and- mysql –

不是重复的，另一个问题在打开的事务中不会失败。 –

不，但这是一个通信链路故障，这是您的根本原因。 – Gimby

这种固定有一个工人来管理数据库连接

来源

2016-11-02 19:25:31

org.hibernate.exception.JDBCConnectionException：无法打开连接时打开transcation

回答

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