daofactory.java

jsp ,java写的blog软件,用到hibernate,spring frameworks

package cn.hxex.blog.dao;

import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.digester.Digester;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xml.sax.SAXException;

import cn.hxex.blog.config.BlogConfig;

/**
 * DAO工厂类还负责读取配置文件
 */
public class DaoFactory {

	private static Log log = LogFactory.getLog(DaoFactory.class);

	// 全局的配置信息对象
	public static final BlogConfig blogConfig;

	// 进行XML文件向Java对象的转换
	static {
		Digester digester = new Digester();
		digester.setValidating(false);

		// 设置处理规则
		digester.addObjectCreate("config", "cn.hxex.blog.config.BlogConfig");
		digester.addSetProperties("config");

		digester.addObjectCreate("config/dao", "cn.hxex.blog.config.DaoConfig");
		digester.addSetProperties("config/dao");
		
		digester.addSetNext("config/dao", "addDao",
				"cn.hxex.blog.config.DaoConfig");

		ClassLoader classLoader = Thread.currentThread()
				.getContextClassLoader();
		InputStream in = classLoader.getResourceAsStream("BlogConfig.xml");
		BlogConfig config = null;
		try {
			if (in != null)
				config = (BlogConfig) digester.parse(in);
		} catch (IOException e) {
			e.printStackTrace();
		} catch (SAXException e) {
			e.printStackTrace();
		}
		blogConfig = config;
	}

	// 取得Dao的实例
	public static Object getDao(String name) {
		if (null == blogConfig)
			return null;

		if (log.isInfoEnabled()) {
			log.info("Getting the dao:" + name);
		}

		return blogConfig.getDao(name);
	}

	public static IUserDAO getUserDAO() {
		log.info("Getting the userDao...");
		return (IUserDAO) getDao("userDao");
	}

	public static IMessageDAO getMessageDAO() {
		log.info("Getting the messageDao...");
		return (IMessageDAO) getDao("messageDao");
	}
}