Java tutorial
/* Copyright 2003 Sun Microsystems, Inc. ALL RIGHTS RESERVED. Use of this software is authorized pursuant to the terms of the license found at http://developer.java.sun.com/berkeley_license.html. Copyright 2003 Sun Microsystems, Inc. All Rights Reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: - Redistribution of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistribution in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of Sun Microsystems, Inc. or the names of contributors may be used to endorse or promote products derived from this software without specific prior written permission. This software is provided "AS IS," without a warranty of any kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICORSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. You acknowledge that this software is not designed, licensed or intended for use in the design, construction, operation or maintenance of any nuclear facility. */ /* * Copyright 2003 Sun Microsystems, Inc. ALL RIGHTS RESERVED. * Use of this software is authorized pursuant to the terms of the license found at * http://developer.java.sun.com/berkeley_license.html. */ import java.sql.*; public class SetSavepoint { public static void main(String args[]) { String url = "jdbc:mySubprotocol:myDataSource"; try { Class.forName("myDriver.className"); } catch (java.lang.ClassNotFoundException e) { System.err.print("ClassNotFoundException: "); System.err.println(e.getMessage()); } try { Connection con = DriverManager.getConnection(url, "myLogin", "myPassword"); con.setAutoCommit(false); String query = "SELECT COF_NAME, PRICE FROM COFFEES " + "WHERE TOTAL > ?"; String update = "UPDATE COFFEES SET PRICE = ? " + "WHERE COF_NAME = ?"; PreparedStatement getPrice = con.prepareStatement(query); PreparedStatement updatePrice = con.prepareStatement(update); getPrice.setInt(1, 7000); ResultSet rs = getPrice.executeQuery(); Savepoint save1 = con.setSavepoint(); while (rs.next()) { String cof = rs.getString("COF_NAME"); float oldPrice = rs.getFloat("PRICE"); float newPrice = oldPrice + (oldPrice * .05f); updatePrice.setFloat(1, newPrice); updatePrice.setString(2, cof); updatePrice.executeUpdate(); System.out.println("New price of " + cof + " is " + newPrice); if (newPrice > 11.99) { con.rollback(save1); } } getPrice = con.prepareStatement(query); updatePrice = con.prepareStatement(update); getPrice.setInt(1, 8000); rs = getPrice.executeQuery(); System.out.println(); Savepoint save2 = con.setSavepoint(); while (rs.next()) { String cof = rs.getString("COF_NAME"); float oldPrice = rs.getFloat("PRICE"); float newPrice = oldPrice + (oldPrice * .05f); updatePrice.setFloat(1, newPrice); updatePrice.setString(2, cof); updatePrice.executeUpdate(); System.out.println("New price of " + cof + " is " + newPrice); if (newPrice > 11.99) { con.rollback(save2); } } con.commit(); Statement stmt = con.createStatement(); rs = stmt.executeQuery("SELECT COF_NAME, " + "PRICE FROM COFFEES"); System.out.println(); while (rs.next()) { String name = rs.getString("COF_NAME"); float price = rs.getFloat("PRICE"); System.out.println("Current price of " + name + " is " + price); } con.close(); } catch (Exception e) { e.printStackTrace(); } } }