Java tutorial
/* This program is a part of the companion code for Core Java 8th ed. (http://horstmann.com/corejava) This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ import java.sql.*; import java.io.*; import java.util.*; /** * This program tests that the database and the JDBC driver are correctly configured. * @version 1.01 2004-09-24 * @author Cay Horstmann */ class TestDB { public static void main(String args[]) { try { runTest(); } catch (SQLException ex) { for (Throwable t : ex) t.printStackTrace(); } catch (IOException ex) { ex.printStackTrace(); } } /** * Runs a test by creating a table, adding a value, showing the table contents, and removing the * table. */ public static void runTest() throws SQLException, IOException { Connection conn = getConnection(); try { Statement stat = conn.createStatement(); stat.executeUpdate("CREATE TABLE Greetings (Message CHAR(20))"); stat.executeUpdate("INSERT INTO Greetings VALUES ('Hello, World!')"); ResultSet result = stat.executeQuery("SELECT * FROM Greetings"); if (result.next()) System.out.println(result.getString(1)); result.close(); stat.executeUpdate("DROP TABLE Greetings"); } finally { conn.close(); } } /** * Gets a connection from the properties specified in the file database.properties * @return the database connection */ public static Connection getConnection() throws SQLException, IOException { Properties props = new Properties(); FileInputStream in = new FileInputStream("database.properties"); props.load(in); in.close(); String drivers = props.getProperty("jdbc.drivers"); if (drivers != null) System.setProperty("jdbc.drivers", drivers); String url = props.getProperty("jdbc.url"); String username = props.getProperty("jdbc.username"); String password = props.getProperty("jdbc.password"); return DriverManager.getConnection(url, username, password); } } //File: database.properties #jdbc.drivers=org.apache.derby.jdbc.ClientDriver jdbc.url=jdbc:derby://localhost:1527/COREJAVA;create=true jdbc.username=dbuser jdbc.password=secret