Hibernate根据方言dialect动态连接多数据库

Hibernate根据方言dialect动态连接多数据库 

由于最近需要在web项目中动态链接不同地址的数据库，且要链接的子数据库的信息在总数据库（即web项目的主数据库）的表中，所以动手写了一个类。 

web项目试用了hibernate，动态生成的子数据库链接打算也用hibernate，虽然动态生成的sessionfactory类，以及Configuration配置没有子数据库的对象关系映射，但是使用 native SQL 也方便。

代码如下：

public class TempSessionFactory {

    /**
     * Location of hibernate.cfg.xml file.
     * Location should be on the classpath as Hibernate uses
     * #resourceAsStream style lookup for its configuration file.
     * The default classpath location of the hibernate config file is
     * in the default package. Use #setConfigFile() to update
     * the location of the configuration file for the current session.
     */
    //private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
    private final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
    private Configuration configuration = new Configuration();
    private org.hibernate.SessionFactory sessionFactory;
    //private static String configFile = CONFIG_FILE_LOCATION;

/*  static {
        try {
            configuration.configure(configFile);
            sessionFactory = configuration.buildSessionFactory();
        } catch (Exception e) {
            System.err
                    .println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }*/

    public void setConfiguration(String dialect, String driverClass,
            String ipAddress, String port, String dataBaseName,
            String username, String password) {
        String connection_url = "";

        Configuration configuration = new Configuration();
        if (dialect.indexOf("MySQL") > -1) {
            System.out.println("%%%% DataBase type is MySql %%%%");
            connection_url = "jdbc:mysql://" + ipAddress + "/" + dataBaseName;
        } else if (dialect.indexOf("SQLServer") > -1) {
            System.out.println("%%%% DataBase type is SQLServer %%%%");
            connection_url = "jdbc:sqlserver://" + ipAddress + ":" + port
                    + ";DataBaseName=" + dataBaseName;
        } else if (dialect.indexOf("Oracle") > -1) {
            System.out.println("%%%% DataBase type is Oracle %%%%");
            connection_url = "jdbc:oracle:thin:@" + ipAddress + ":" + port
                    + ":" + dataBaseName;
            // configuration.setProperty("hibernate.connection.oracle.jdbc.V8Compatible","true");
        }

        configuration.setProperty("hibernate.dialect", dialect);
        configuration.setProperty("hibernate.connection.url", connection_url);
        configuration.setProperty("hibernate.connection.driver_class",
                driverClass);
        configuration.setProperty("hibernate.connection.username", username);
        configuration.setProperty("hibernate.connection.password", password);
        // configuration.setProperty("hibernate.default_schema", "dbo");
        // configuration.setProperty("hibernate.default_catalog", dataBaseName);
        // configuration.setProperty("hibernate.show_sql", "true");
        this.configuration = configuration;
    }
    /**
     * Returns the ThreadLocal Session instance.  Lazy initialize
     * the <code>SessionFactory</code> if needed.
     *
     *  @return Session
     *  @throws HibernateException
     *
     */
    public Session getSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        if (session == null || !session.isOpen()) {
            if (sessionFactory == null) {
                rebuildSessionFactory();
            }
            session = (sessionFactory != null) ? sessionFactory.openSession()
                    : null;
            threadLocal.set(session);
        }

        return session;
    }

    /**
     *  Rebuild hibernate session factory
     *
     */
    public void rebuildSessionFactory() {
        try {
            //configuration.configure(configFile);
            sessionFactory = this.configuration.buildSessionFactory();
        } catch (Exception e) {
            System.err
                    .println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }

    /**
     *  Close the single hibernate session instance.
     *
     *  @throws HibernateException
     */
    public void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        threadLocal.set(null);

        if (session != null) {
            session.close();
        }
    }

    /**
     *  return session factory
     *
     */
    public org.hibernate.SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    /**
     *  return session factory
     *
     *  session factory will be rebuilded in the next call
     */
/*  public static void setConfigFile(String configFile) {
        HibernateSessionFactory.configFile = configFile;
        sessionFactory = null;
    }*/

    /**
     *  return hibernate configuration
     *
     */
    public Configuration getConfiguration() {
        return configuration;
    }
}

测试类代码： 
在 databasename1 库中建 testtable表，字段id,name2个 
在 databasename2 库中建 testtable2表，字段id,name2个 

public class TestCase1 {

    public static void main(String[] args) {

        try{

            Configuration configuration1 = new Configuration();
            TempSessionFactory tempSessionFactory1 = new TempSessionFactory(configuration1);
            tempSessionFactory1.setConfiguration("org.hibernate.dialect.SQLServerDialect","com.microsoft.sqlserver.jdbc.SQLServerDriver",
                    "jdbc:sqlserver://*1.*1.*1.*1","1433","databasename1","sa","sa");
            Session session1=tempSessionFactory1.getSession();
            Transaction tx1 = session1.beginTransaction();
            Query query1 = session1.createSQLQuery("select  name as  aaa  from testtable ").setResultTransformer(
                    Transformers.ALIAS_TO_ENTITY_MAP);
            Map obj1 = (Map)query1.setMaxResults(1).uniqueResult();
            System.out.println("fd1111===="+obj1.get("aaa"));

            Configuration configuration2 = new Configuration();
            TempSessionFactory tempSessionFactory2 = new TempSessionFactory(configuration2);
            tempSessionFactory2.setConfiguration("org.hibernate.dialect.SQLServerDialect","com.microsoft.sqlserver.jdbc.SQLServerDriver",
                    "jdbc:sqlserver://*2.*2.*2.*2","1433","databasename2","sa","sa");
            Session session2=tempSessionFactory2.getSession();
            Transaction tx2 = session2.beginTransaction();
            Query query2 = session2.createSQLQuery("select  name as  aaa  from testtable2 ").setResultTransformer(
                    Transformers.ALIAS_TO_ENTITY_MAP);
            Map obj2 = (Map)query2.setMaxResults(1).uniqueResult();
            System.out.println("fd2222===="+obj2.get("aaa"));


        }catch (Exception e) {
            System.err.println(e);
            // TODO: handle exception
        }
    }
}