Hibernate动态连接多数据库改进篇

Hibernate动态连接多数据库改进篇

 

本人曾经写过一篇

Hibernate根据方言dialect动态连接多数据库  的文章，发现效率不高，每次访问其他数据库，都要动态生成一个 sessionFactory实例，不算是个好的解决方法，后来查看hibernate源码，发现org.hibernate.cfg.Configuration类中有一个保护方法：

	protected void reset() {
……
	}

 

故重写Configuration类，在动态的跳转不同数据库的时候，不用重新生成sessionFactory实例，发现效果不错。

故以此记录我的方法：

 

1. 自己重写的Configuration类，extends org.hibernate.cfg.Configuration ：

 

public class HibernateConfiguration extends org.hibernate.cfg.Configuration {

	public HibernateConfiguration() {
		super();
	}

	public void reset() {
		super.reset();
	}

	public HibernateConfiguration(String dialect, String driverClass,
			String ipAddress, String port, String dataBaseName,
			String username, String password) throws HibernateException {
		String connection_url = "";
		if (dialect.indexOf("MySQL") > -1) {
			connection_url = "jdbc:mysql://" + ipAddress + "/" + dataBaseName;
		} else if (dialect.indexOf("SQLServer") > -1) {
			connection_url = "jdbc:sqlserver://" + ipAddress + ":" + port
					+ ";DataBaseName=" + dataBaseName;
		} else if (dialect.indexOf("Oracle") > -1) {
			connection_url = "jdbc:oracle:thin:@" + ipAddress + ":" + port
					+ ":" + dataBaseName;
		} else {
			throw new HibernateException("The dialect was not allowed.==fd=="
					+ dialect);
		}

		super.setProperty("hibernate.dialect", dialect);
		super.setProperty("hibernate.connection.url", connection_url);
		super.setProperty("hibernate.connection.driver_class", driverClass);
		super.setProperty("hibernate.connection.username", username);
		super.setProperty("hibernate.connection.password", password);
		// super.setProperty("hibernate.show_sql", "true");
	}

	public HibernateConfiguration(String dialect, String driverClass,
			String ipAddress, String port, String dataBaseName,
			String username, String password, String schema, String catalog)
			throws HibernateException {
		String connection_url = "";
		if (dialect.indexOf("MySQL") > -1) {
			connection_url = "jdbc:mysql://" + ipAddress + "/" + dataBaseName;
		} else if (dialect.indexOf("SQLServer") > -1) {
			connection_url = "jdbc:sqlserver://" + ipAddress + ":" + port
					+ ";DataBaseName=" + dataBaseName;
		} else if (dialect.indexOf("Oracle") > -1) {
			connection_url = "jdbc:oracle:thin:@" + ipAddress + ":" + port
					+ ":" + dataBaseName;
		} else {
			throw new HibernateException("The dialect was not allowed.==fd=="
					+ dialect);
		}

		super.setProperty("hibernate.dialect", dialect);
		super.setProperty("hibernate.connection.url", connection_url);
		super.setProperty("hibernate.connection.driver_class", driverClass);
		super.setProperty("hibernate.connection.username", username);
		super.setProperty("hibernate.connection.password", password);
		super.setProperty("hibernate.default_schema", schema);
		super.setProperty("hibernate.default_catalog", catalog);
		// super.setProperty("hibernate.show_sql", "true");
	}

}

 

2. TempSessionFactory 的工厂类，这里把各个对象都变成了 static ，类也是static 类了，每次调用，都不用生成一个sessionFactory实例了，主要还是自己定义了一个reflashSessionFactory方法，对每次不同的数据库连接进行动态加载，其他的就是hibernate.cfg.xml 加载的问题，首次默认加载是用hibernate2.cfg.xml，其他时候就才用最新设置的参数，用了自定义类HibernateConfiguration 。 见下：

 

import org.hibernate.HibernateException;
import org.hibernate.Session;
import com.tools.hibernate.utils.HibernateConfiguration;

public class TempSessionFactory {

	.......//略


	public static void reflashSessionFactory(
			HibernateConfiguration tempConfiguration) {
		try {
			// configuration.configure(configFile);
			if (tempConfiguration.getProperty("hibernate.dialect").equals(
					configuration.getProperty("hibernate.dialect"))
					&& tempConfiguration
							.getProperty("hibernate.connection.url")
							.equalsIgnoreCase(
									configuration
											.getProperty("hibernate.connection.url"))
					&& tempConfiguration
							.getProperty("hibernate.connection.username")
							.equals(
									configuration
											.getProperty("hibernate.connection.username"))
					&& tempConfiguration
							.getProperty("hibernate.connection.password")
							.equals(
									configuration
											.getProperty("hibernate.connection.password"))) {

				System.out.println("%%%% TempSessionFactory is created aready!!-fd %%%%");
				// sessionFactory = configuration.buildSessionFactory();
			} else {
				closeSession();
				closeSessionFactory();
				configuration.reset();
				configuration = tempConfiguration;
				sessionFactory = configuration.buildSessionFactory();
				System.out.println("%%%% TempSessionFactory is reflashed here!!-fd %%%%");
			}
		} catch (Exception e) {
			System.err.println("%%%% Error Reflashing TempSessionFactory %%%%");
			e.printStackTrace();
		}
	}

	......//略
}

 

3. 顺便发一下测试类，自己在不同服务器上面 建几个数据库，建几张测试表，就可以了：

 

	public static void main(String[] args) {
		try{
			
			String timeFormat = "yyyy-MM-dd HH:mm:ss";
			SimpleDateFormat sdf = new SimpleDateFormat(timeFormat); 

			
			HibernateConfiguration configuration1 = new HibernateConfiguration("org.hibernate.dialect.SQLServerDialect","com.microsoft.sqlserver.jdbc.SQLServerDriver",
					"255.255.255.255","1433","dbname1","sa","sa");
			System.out.println("hibernate.connection.url==1="+TempSessionFactory.getConfiguration().getProperty("hibernate.connection.url"));
			TempSessionFactory.reflashSessionFactory(configuration1);			
			System.out.println("hibernate.connection.url==2="+TempSessionFactory.getConfiguration().getProperty("hibernate.connection.url"));
			
			Session session1=TempSessionFactory.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"));

			
			
			
			System.out.println("hibernate.connection.url==3="+TempSessionFactory.getConfiguration().getProperty("hibernate.connection.url"));
			HibernateConfiguration configuration2 = new HibernateConfiguration("org.hibernate.dialect.Oracle10gDialect","oracle.jdbc.driver.OracleDriver",
					"255.255.255.255","1521","orclDB1","username","passwd");			
			TempSessionFactory.reflashSessionFactory(configuration2);
			
			System.out.println("hibernate.connection.url==4="+TempSessionFactory.getConfiguration().getProperty("hibernate.connection.url"));
			session1=TempSessionFactory.getSession();
			tx1 = session1.beginTransaction();
			Query query2 = session1.createSQLQuery("select testname1 AAA from testtable1 ").setResultTransformer(
					Transformers.ALIAS_TO_ENTITY_MAP);
			Map obj2 = (Map)query2.setMaxResults(1).uniqueResult();
			System.out.println("fd2222===="+obj2.get("AAA"));
			
			
			
			
			System.out.println("hibernate.connection.url==5="+TempSessionFactory.getConfiguration().getProperty("hibernate.connection.url"));
			HibernateConfiguration configuration3 = new HibernateConfiguration("org.hibernate.dialect.Oracle10gDialect","oracle.jdbc.driver.OracleDriver",
					"255.255.255.255","1521","orclDB2","username","passwd");
			TempSessionFactory.reflashSessionFactory(configuration3);
			System.out.println("hibernate.connection.url==6="+TempSessionFactory.getConfiguration().getProperty("hibernate.connection.url"));
			session1=TempSessionFactory.getSession();
			tx1 = session1.beginTransaction();
			Query query3 = session1.createSQLQuery("select testname1 AAA from testtable2 ").setResultTransformer(
					Transformers.ALIAS_TO_ENTITY_MAP);
			Map obj3 = (Map)query3.setMaxResults(1).uniqueResult();
			System.out.println("fd3333===="+obj3.get("AAA"));
			
			
		}catch (Exception e) {
			System.err.println(e);
		}
	}

 

有什么好的建议，请留言。。。。。。。。。。。。。。。。。。。

转载注明 出处。。。。。。。。。。。。。。。。。。。。。。。。。

 

评论

5 楼 HelloJava1234 2013-08-13  

对lz的代码做了改进，需要的可以参考下，本人菜鸟一个，有不足的请别介意！http://blog.csdn.net/hellojava1234/article/details/9949359

4 楼 chhsf 2012-12-31  

你好，feicer。
请问，hibernate.cfg.xml加载问题如何处理。是在不同的服务器上有各自的hibernate.cfg.xml文件吗？如果我的对象映射都是相同的，是否可以只加载一个hibernate.cfg.xml文件。我用的是hibernate.cfg.xml+Proxool.xml。

3 楼 gaolinwu 2012-03-08  

强烈推荐“1楼”的问题，希望楼主给出建议性措施！

2 楼 tanjunxiaoge 2011-11-22  

对，1楼这个问题值得考虑一下

1 楼 gybddp 2011-10-15  

请问如果结合spring，由spring管理hibernate，如何实现动态链接数据库？