MyBatis的MySqlSessionFactory

MyBatis

之前的获取SqlSession是线程不安全的。故对session的获取采用hibernate的方式重新封装了一个sessionFactory!

public class MyBatisUtil {

   
    private static final ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>();
    private static SqlSessionFactory sessionFactory;
	
    private static String CONFIG_FILE_LOCATION = "myBatis-config.xml";

	static {
    	try {
    		buildSessionFactory();
		} catch (Exception e) {
			System.err.println("%%%% Error Creating SessionFactory %%%%");
			e.printStackTrace();
		}
    }
    private MyBatisUtil() {
    }
	
	/**
     * Returns the ThreadLocal Session instance.  Lazy initialize
     * the <code>SessionFactory</code> if needed.
     *
     *  @return Session
     *  @throws Exception
     */
    public static SqlSession getSession() throws Exception {
        SqlSession session = (SqlSession) threadLocal.get();

		if (session == null) {
			if (sessionFactory == null) {
				buildSessionFactory();
			}
			session = (sessionFactory != null) ? sessionFactory.openSession()
					: null;
			threadLocal.set(session);
		}

        return session;
    }

	/**
     *  build  session factory
     *
     */
	public static void buildSessionFactory() {
		Reader reader=null;
		try {
			reader=Resources.getResourceAsReader(CONFIG_FILE_LOCATION);
			sessionFactory = new SqlSessionFactoryBuilder().build(reader);
		} catch (Exception e) {
			System.err.println("%%%% Error Creating SessionFactory %%%%");
			e.printStackTrace();
		}finally{
			try {
				reader.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	/**
     *  Close the single  session instance.
     *
     */
    public static void closeSession(){
        SqlSession session = (SqlSession) threadLocal.get();
        threadLocal.set(null);

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

	/**
     *  return session factory
     *
     */
	public static SqlSessionFactory getSessionFactory() {
		return sessionFactory;
	}
}