| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 |
| * |
| * http://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. |
| */ |
| |
| import java.sql.Connection; |
| import java.sql.DriverManager; |
| import java.sql.ResultSet; |
| import java.sql.SQLException; |
| import java.sql.Statement; |
| |
| import org.apache.commons.dbcp2.ConnectionFactory; |
| import org.apache.commons.dbcp2.DriverManagerConnectionFactory; |
| import org.apache.commons.dbcp2.PoolableConnection; |
| import org.apache.commons.dbcp2.PoolableConnectionFactory; |
| import org.apache.commons.dbcp2.PoolingDriver; |
| // |
| // Here are the dbcp-specific classes. |
| // Note that they are only used in the setupDriver |
| // method. In normal use, your classes interact |
| // only with the standard JDBC API |
| // |
| import org.apache.commons.pool2.ObjectPool; |
| import org.apache.commons.pool2.impl.GenericObjectPool; |
| |
| // |
| // Here's a simple example of how to use the PoolingDriver. |
| // |
| |
| // To compile this example, you'll want: |
| // * commons-pool-2.3.jar |
| // * commons-dbcp-2.1.jar |
| // in your classpath. |
| // |
| // To run this example, you'll want: |
| // * commons-pool-2.3.jar |
| // * commons-dbcp-2.1.jar |
| // * commons-logging-1.2.jar |
| // in your classpath. |
| // |
| // Invoke the class using two arguments: |
| // * the connect string for your underlying JDBC driver |
| // * the query you'd like to execute |
| // You'll also want to ensure your underlying JDBC driver |
| // is registered. You can use the "jdbc.drivers" |
| // property to do this. |
| // |
| // For example: |
| // java -Djdbc.drivers=org.h2.Driver \ |
| // -classpath commons-pool2-2.3.jar:commons-dbcp2-2.1.jar:commons-logging-1.2.jar:h2-1.3.152.jar:. \ |
| // PoolingDriverExample \ |
| // "jdbc:h2:~/test" \ |
| // "SELECT 1" |
| // |
| public class PoolingDriverExample { |
| |
| public static void main(String[] args) { |
| // |
| // First we load the underlying JDBC driver. |
| // You need this if you don't use the jdbc.drivers |
| // system property. |
| // |
| System.out.println("Loading underlying JDBC driver."); |
| try { |
| Class.forName("org.h2.Driver"); |
| } catch (ClassNotFoundException e) { |
| e.printStackTrace(); |
| } |
| System.out.println("Done."); |
| |
| // |
| // Then we set up and register the PoolingDriver. |
| // Normally this would be handled auto-magically by |
| // an external configuration, but in this example we'll |
| // do it manually. |
| // |
| System.out.println("Setting up driver."); |
| try { |
| setupDriver(args[0]); |
| } catch (Exception e) { |
| e.printStackTrace(); |
| } |
| System.out.println("Done."); |
| |
| // |
| // Now, we can use JDBC as we normally would. |
| // Using the connect string |
| // jdbc:apache:commons:dbcp:example |
| // The general form being: |
| // jdbc:apache:commons:dbcp:<name-of-pool> |
| // |
| |
| Connection conn = null; |
| Statement stmt = null; |
| ResultSet rset = null; |
| |
| try { |
| System.out.println("Creating connection."); |
| conn = DriverManager.getConnection("jdbc:apache:commons:dbcp:example"); |
| System.out.println("Creating statement."); |
| stmt = conn.createStatement(); |
| System.out.println("Executing statement."); |
| rset = stmt.executeQuery(args[1]); |
| System.out.println("Results:"); |
| int numcols = rset.getMetaData().getColumnCount(); |
| while(rset.next()) { |
| for(int i=1;i<=numcols;i++) { |
| System.out.print("\t" + rset.getString(i)); |
| } |
| System.out.println(""); |
| } |
| } catch(SQLException e) { |
| e.printStackTrace(); |
| } finally { |
| try { if (rset != null) rset.close(); } catch(Exception e) { } |
| try { if (stmt != null) stmt.close(); } catch(Exception e) { } |
| try { if (conn != null) conn.close(); } catch(Exception e) { } |
| } |
| |
| // Display some pool statistics |
| try { |
| printDriverStats(); |
| } catch (Exception e) { |
| e.printStackTrace(); |
| } |
| |
| // closes the pool |
| try { |
| shutdownDriver(); |
| } catch (Exception e) { |
| e.printStackTrace(); |
| } |
| } |
| |
| public static void setupDriver(String connectURI) throws Exception { |
| // |
| // First, we'll create a ConnectionFactory that the |
| // pool will use to create Connections. |
| // We'll use the DriverManagerConnectionFactory, |
| // using the connect string passed in the command line |
| // arguments. |
| // |
| ConnectionFactory connectionFactory = |
| new DriverManagerConnectionFactory(connectURI,null); |
| |
| // |
| // Next, we'll create the PoolableConnectionFactory, which wraps |
| // the "real" Connections created by the ConnectionFactory with |
| // the classes that implement the pooling functionality. |
| // |
| PoolableConnectionFactory poolableConnectionFactory = |
| new PoolableConnectionFactory(connectionFactory, null); |
| |
| // |
| // Now we'll need a ObjectPool that serves as the |
| // actual pool of connections. |
| // |
| // We'll use a GenericObjectPool instance, although |
| // any ObjectPool implementation will suffice. |
| // |
| ObjectPool<PoolableConnection> connectionPool = |
| new GenericObjectPool<>(poolableConnectionFactory); |
| |
| // Set the factory's pool property to the owning pool |
| poolableConnectionFactory.setPool(connectionPool); |
| |
| // |
| // Finally, we create the PoolingDriver itself... |
| // |
| Class.forName("org.apache.commons.dbcp2.PoolingDriver"); |
| PoolingDriver driver = (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:"); |
| |
| // |
| // ...and register our pool with it. |
| // |
| driver.registerPool("example",connectionPool); |
| |
| // |
| // Now we can just use the connect string "jdbc:apache:commons:dbcp:example" |
| // to access our pool of Connections. |
| // |
| } |
| |
| public static void printDriverStats() throws Exception { |
| PoolingDriver driver = (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:"); |
| ObjectPool<? extends Connection> connectionPool = driver.getConnectionPool("example"); |
| |
| System.out.println("NumActive: " + connectionPool.getNumActive()); |
| System.out.println("NumIdle: " + connectionPool.getNumIdle()); |
| } |
| |
| public static void shutdownDriver() throws Exception { |
| PoolingDriver driver = (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:"); |
| driver.closePool("example"); |
| } |
| } |