BaseDao的封装

版权声明： https://blog.csdn.net/No_mingzi/article/details/90602295

书城项目，basedao封装模板（参考）

public abstract class BaseDao {

	QueryRunner queryRunner = new QueryRunner();

	/**
	 * update方法执行insert、update、delete语句
	 * 
	 * @return
	 */
	public int update(String sql, Object... args) {

		Connection connection = JdbcUtils.getConnection();

		try {
			return queryRunner.update(connection, sql, args);
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			JdbcUtils.close(connection);
		}

		return -1;

	}

	/**
	 * 执行select查询语句，查询返回一个javaBean的sql
	 * 
	 * @param type
	 * @param sql
	 * @param args
	 * @return
	 */
	public <T> T queryForOne(Class<T> type, String sql, Object... args) {
		Connection connection = JdbcUtils.getConnection();

		try {
			return queryRunner.query(connection, sql, new BeanHandler<T>(type),
					args);
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			JdbcUtils.close(connection);
		}

		return null;

	}

	public <T> List<T> queryForList(Class<T> type, String sql, Object... args) {

		Connection connection = JdbcUtils.getConnection();

		try {
			return queryRunner.query(connection, sql, new BeanListHandler<T>(
					type), args);
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			JdbcUtils.close(connection);
		}

		return null;

	}

}