Java tutorial
/* * Copyright 2002-2018 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.jdbc.datasource; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.Properties; import org.springframework.util.Assert; import org.springframework.util.ClassUtils; /** * Simple implementation of the standard JDBC {@link javax.sql.DataSource} interface, * configuring the plain old JDBC {@link java.sql.DriverManager} via bean properties, and * returning a new {@link java.sql.Connection} from every {@code getConnection} call. * * <p><b>NOTE: This class is not an actual connection pool; it does not actually * pool Connections.</b> It just serves as simple replacement for a full-blown * connection pool, implementing the same standard interface, but creating new * Connections on every call. * * <p>Useful for test or standalone environments outside of a Java EE container, either * as a DataSource bean in a corresponding ApplicationContext or in conjunction with * a simple JNDI environment. Pool-assuming {@code Connection.close()} calls will * simply close the Connection, so any DataSource-aware persistence code should work. * * <p><b>NOTE: Within special class loading environments such as OSGi, this class * is effectively superseded by {@link SimpleDriverDataSource} due to general class * loading issues with the JDBC DriverManager that be resolved through direct Driver * usage (which is exactly what SimpleDriverDataSource does).</b> * * <p>In a Java EE container, it is recommended to use a JNDI DataSource provided by * the container. Such a DataSource can be exposed as a DataSource bean in a Spring * ApplicationContext via {@link org.springframework.jndi.JndiObjectFactoryBean}, * for seamless switching to and from a local DataSource bean like this class. * For tests, you can then either set up a mock JNDI environment through Spring's * {@link org.springframework.mock.jndi.SimpleNamingContextBuilder}, or switch the * bean definition to a local DataSource (which is simpler and thus recommended). * * <p>If you need a "real" connection pool outside of a Java EE container, consider * <a href="https://commons.apache.org/proper/commons-dbcp">Apache Commons DBCP</a> * or <a href="https://sourceforge.net/projects/c3p0">C3P0</a>. * Commons DBCP's BasicDataSource and C3P0's ComboPooledDataSource are full * connection pool beans, supporting the same basic properties as this class * plus specific settings (such as minimal/maximal pool size etc). * * @author Juergen Hoeller * @since 14.03.2003 * @see SimpleDriverDataSource */ public class DriverManagerDataSource extends AbstractDriverBasedDataSource { /** * Constructor for bean-style configuration. */ public DriverManagerDataSource() { } /** * Create a new DriverManagerDataSource with the given JDBC URL, * not specifying a username or password for JDBC access. * @param url the JDBC URL to use for accessing the DriverManager * @see java.sql.DriverManager#getConnection(String) */ public DriverManagerDataSource(String url) { setUrl(url); } /** * Create a new DriverManagerDataSource with the given standard * DriverManager parameters. * @param url the JDBC URL to use for accessing the DriverManager * @param username the JDBC username to use for accessing the DriverManager * @param password the JDBC password to use for accessing the DriverManager * @see java.sql.DriverManager#getConnection(String, String, String) */ public DriverManagerDataSource(String url, String username, String password) { setUrl(url); setUsername(username); setPassword(password); } /** * Create a new DriverManagerDataSource with the given JDBC URL, * not specifying a username or password for JDBC access. * @param url the JDBC URL to use for accessing the DriverManager * @param conProps the JDBC connection properties * @see java.sql.DriverManager#getConnection(String) */ public DriverManagerDataSource(String url, Properties conProps) { setUrl(url); setConnectionProperties(conProps); } /** * Set the JDBC driver class name. This driver will get initialized * on startup, registering itself with the JDK's DriverManager. * <p><b>NOTE: DriverManagerDataSource is primarily intended for accessing * <i>pre-registered</i> JDBC drivers.</b> If you need to register a new driver, * consider using {@link SimpleDriverDataSource} instead. Alternatively, consider * initializing the JDBC driver yourself before instantiating this DataSource. * The "driverClassName" property is mainly preserved for backwards compatibility, * as well as for migrating between Commons DBCP and this DataSource. * @see java.sql.DriverManager#registerDriver(java.sql.Driver) * @see SimpleDriverDataSource */ public void setDriverClassName(String driverClassName) { Assert.hasText(driverClassName, "Property 'driverClassName' must not be empty"); String driverClassNameToUse = driverClassName.trim(); try { Class.forName(driverClassNameToUse, true, ClassUtils.getDefaultClassLoader()); } catch (ClassNotFoundException ex) { throw new IllegalStateException("Could not load JDBC driver class [" + driverClassNameToUse + "]", ex); } if (logger.isDebugEnabled()) { logger.debug("Loaded JDBC driver: " + driverClassNameToUse); } } @Override protected Connection getConnectionFromDriver(Properties props) throws SQLException { String url = getUrl(); Assert.state(url != null, "'url' not set"); if (logger.isDebugEnabled()) { logger.debug("Creating new JDBC DriverManager Connection to [" + url + "]"); } return getConnectionFromDriverManager(url, props); } /** * Getting a Connection using the nasty static from DriverManager is extracted * into a protected method to allow for easy unit testing. * @see java.sql.DriverManager#getConnection(String, java.util.Properties) */ protected Connection getConnectionFromDriverManager(String url, Properties props) throws SQLException { return DriverManager.getConnection(url, props); } }