public class jdbcTest {

	/**
	 * 建立表
	 */
	public static void createTable() throws SQLException{
		String sql = "CREATE TABLE IF NOT EXISTS `user`("
			     +"`id` INT UNSIGNED AUTO_INCREMENT,"
			  	 +" `user_name` VARCHAR(100),"
			  	 +" `user_password` VARCHAR(100),"
			  	 +" `user_age` INT(11),"
			  	 +"PRIMARY KEY ( `id` )"
			  	 +")ENGINE=InnoDB DEFAULT CHARSET=utf8;";
		Connection conn = DBUtil.getConnection();
		//開啟事務
		conn.setAutoCommit(false);
		PreparedStatement preparedStatement = conn.prepareStatement(sql);
		preparedStatement.executeUpdate();
		//提交事務
		conn.commit();
		//要注意關閉連線（在實際中最好不要像這樣關閉，最好標準一點）
		conn.close();
	}
	
	/**
	 * 增加資料
	 */
	public static void add() throws SQLException{
		String sql = "INSERT INTO USER (user_name,user_password,user_age) VALUES('老王','123456',18)";
		Connection conn = DBUtil.getConnection();
		conn.setAutoCommit(false);
		PreparedStatement preparedStatement = conn.prepareStatement(sql);
		preparedStatement.executeUpdate();
		conn.commit();
		conn.close();
	}
	
	/**
	 * 刪除資料
	 */
	public static void delete() throws SQLException{
		String sql = "DELETE FROM USER WHERE USER.user_name = '老王'";
		Connection conn = DBUtil.getConnection();
		conn.setAutoCommit(false);
		PreparedStatement preparedStatement = conn.prepareStatement(sql);
		preparedStatement.executeUpdate();
		conn.commit();
		conn.close();
	}
	
	/**
	 * 修改資料
	 */
	public static void updata() throws SQLException{
		String sql = "UPDATE USER SET USER.user_name = '老李'";
		Connection conn = DBUtil.getConnection();
		conn.setAutoCommit(false);
		PreparedStatement preparedStatement = conn.prepareStatement(sql);
		preparedStatement.executeUpdate();
		conn.commit();
		conn.close();
	}
	
	/**
	 * 查詢資料
	 */
	public static void query() throws SQLException{
		String sql = "SELECT * FROM USER";
		Connection conn = DBUtil.getConnection();
		conn.setAutoCommit(false);
		PreparedStatement preparedStatement = conn.prepareStatement(sql);
		//執行查詢語句並返回結果集
		ResultSet resultSet = preparedStatement.executeQuery();
		while (resultSet.next()) {
			//注意：這裡要與資料庫裡的欄位對應
			String username = resultSet.getString("user_name");
			String password = resultSet.getString("user_password");
			String age = resultSet.getString("user_age");
			System.out.println(username + " " + password + " " + age);
		}
		conn.commit();
		conn.close();
	}
}