Hibernates.java

package com.fang.bbks.common.persistence;

import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;

import org.apache.commons.lang3.StringUtils;
import org.hibernate.Hibernate;
import org.hibernate.dialect.H2Dialect;
import org.hibernate.dialect.MySQL5InnoDBDialect;
import org.hibernate.dialect.Oracle10gDialect;

/**
 * Hibernates 工具类
 * @version 2013-01-15
 */
public class Hibernates {

	/**
	 * Initialize the lazy property value, eg.
	 * Hibernates.initLazyProperty(user.getRoles()); 
	 */
	public static void initLazyProperty(Object proxyedPropertyValue) {
		Hibernate.initialize(proxyedPropertyValue);
	}

	/**
	 * 从DataSoure中取出connection, 根据connection的metadata中的jdbcUrl判断Dialect类型.
	 */
	public static String getDialect(DataSource dataSource) {
		//从DataSource中取出jdbcUrl.
		String jdbcUrl = null;
		Connection connection = null;
		try {
			connection = dataSource.getConnection();
			if (connection == null) {
				throw new IllegalStateException("Connection returned by DataSource [" + dataSource + "] was null");
			}
			jdbcUrl = connection.getMetaData().getURL();
		} catch (SQLException e) {
			throw new RuntimeException("Could not get database url", e);
		} finally {
			if (connection != null) {
				try {
					connection.close();
				} catch (SQLException e) {
					connection = null;
				}
			}
		}
		//根据jdbc url判断dialect
		if (StringUtils.contains(jdbcUrl, ":h2:")) {
			return H2Dialect.class.getName();
		} else if (StringUtils.contains(jdbcUrl, ":mysql:")) {
			return MySQL5InnoDBDialect.class.getName();
		} else if (StringUtils.contains(jdbcUrl, ":oracle:")) {
			return Oracle10gDialect.class.getName();
		} else {
			throw new IllegalArgumentException("Unknown Database");
		}
	}
}