Hibernate 5 + HikariCP + MySQL

问题

I've started a project using Hibernate 5 and a MySQL database. Prior to this project, I've been using Hibernate 4, PostgreSQL and C3P0 connection pool.

Now, I want to use HikariCP as it seems really promising, with Hibernate 5.

Here it's my IVY configuration part for hibernate:

     <?xml version="1.0"?>
     <!DOCTYPE ivy-module [
         <!ENTITY vaadin.version "7.5.5">
         <!ENTITY highcharts.version "1.1">
         <!ENTITY vaadin.charts.version "3.0.0-alpha5">

         <!ENTITY hibernate.version "5.0.1.Final">
         <!ENTITY mysql.version "5.1.36">
         <!ENTITY log4j.version "2.3">
         <!ENTITY apache.poi.version "3.12">
         <!ENTITY apache.commons.io.version "2.4">

     ]>     
     ...          
    <!-- Hibernate -->
    <dependency org="org.hibernate" name="hibernate-core" rev="&hibernate.version;" /><!-- core -->
    <dependency org="org.hibernate" name="hibernate-java8" rev="&hibernate.version;" /><!-- java 8 support -->
    <!-- Connection Pool: -->
        <dependency org="org.hibernate" name="hibernate-hikaricp" rev="&hibernate.version;" /><!-- hikariCP -->

My DAO seems like this:

public class PtDao {

    private Logger logger = LoggerFactory.getLogger(PtDao.class);

    private static PtDao instance;

    private Configuration cfg;
    private static ServiceRegistry serviceRegistry;
    private SessionFactory factory;
    private Transaction tx;
    private static Session session;

    private PtDao(){

        prepararConexionConHikariCP();

    }


    private void prepararConexionConHikariCP(){

        try{

            cfg = new Configuration();

            cfg.setProperty("hibernate.hbm2ddl.auto", "update");
            cfg.setProperty("hibernate.transaction.auto_close_session", "true");
            cfg.setProperty("hibernate.connection.autocommit", "false");

            cfg.setProperty("hibernate.connection.provider_class", "com.zaxxer.hikari.hibernate.HikariConnectionProvider");
            cfg.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");

            cfg.setProperty("hibernate.hikari.dataSourceClassName", "com.mysql.jdbc.jdbc2.optional.MysqlDataSource");

            // MySQL Servidor Linux
            cfg.setProperty("hibernate.hikari.dataSource.url", "jdbc:mysql://192.168.1.101:3306/averiassae");
            cfg.setProperty("hibernate.hikari.dataSource.user", "root");
            cfg.setProperty("hibernate.hikari.dataSource.password", "XXXXX");

            cfg.setProperty("hibernate.hikari.dataSource.cachePrepStmts", "true");
            cfg.setProperty("hibernate.hikari.dataSource.prepStmtCacheSize", "250");
            cfg.setProperty("hibernate.hikari.dataSource.prepStmtCacheSqlLimit", "2048");

            //cfg.setProperty("hibernate.hikari.idleTimeout", "300000");
            //cfg.setProperty("hibernate.hikari.minimumIdle", "10");
            //cfg.setProperty("hibernate.hikari.maximumPoolSize", "20");

            cfg.setProperty("hibernate.show_sql", "true");
            cfg.setProperty("hibernate.format_sql", "true");
            cfg.setProperty("hibernate.generate_statistics", "true");

            anyadirPersistencia();

            StandardServiceRegistryBuilder serviceRegistryBuilder = new StandardServiceRegistryBuilder();
            serviceRegistryBuilder.applySettings(cfg.getProperties());

            serviceRegistry = serviceRegistryBuilder.build();

            factory = cfg.buildSessionFactory(serviceRegistry);

            this.openSession();

        } catch (HibernateException e) {
            logger.error("Error HibernateException (" + e.getClass() + ") en PtDao(): " + e.getMessage() + ". Causa: " + e.getCause());
            e.printStackTrace();
        }

    }

    private void anyadirPersistencia() {

        cfg.addAnnotatedClass(Operador.class);
        cfg.addAnnotatedClass(Averia.class);

    }

    ...

It seems that Hikari is well configured, but once and again new connections appear on MySQL Workbench's Administration-Client connections window, even if the application is stopped...

My questions are:

1) Is Hibernate and Hikari well configured?
2) Any clue to manage those connections?

Thanks for your help

来源：https://stackoverflow.com/questions/32821574/hibernate-5-hikaricp-mysql