Connection through ConnectionPoolDataSource

Question

To connect my required database. I plan to use the ConnectionPoolDataSource class. But how can I ask for details about the name of the database (to which I want to connect) when using this instance. Please help in this case.

Answer 1

Try reading this documentation and example.

EDIT

just modified example from above links

prepared steps: - download MySQL Server - download mySQL java driver - download Apache Commons Pool - download Commons DBCP - Open a MySQL client, for example MySQL Workbench, and create a database using the following script

delimiter $$ CREATE DATABASE `test_stackoverflow` /*!40100 DEFAULT CHARACTER SET utf8 */$$ delimiter $$ CREATE TABLE `test_table` ( `idtest_table` int(11) NOT NULL, `test_field` varchar(45) DEFAULT NULL, PRIMARY KEY (`idtest_table`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8$$ INSERT INTO `test_stackoverflow`.`test_table` (`idtest_table`, `test_field`) VALUES (1, 'test1'); INSERT INTO `test_stackoverflow`.`test_table` (`idtest_table`, `test_field`) VALUES (2, 'test2'); 

• create a java project, add the myscl connector, pool and dbcp to the class path (you just load all these banks)

add the following classes

 import org.apache.commons.dbcp.cpdsadapter.DriverAdapterCPDS; import org.apache.commons.dbcp.datasources.SharedPoolDataSource; import javax.sql.DataSource; import java.sql.Connection; import java.sql.SQLException; /** * @author Sergii.Zagriichuk */ public class Pool { private static DataSource ds; static { DriverAdapterCPDS cpds = new DriverAdapterCPDS(); try { cpds.setDriver("com.mysql.jdbc.Driver"); } catch (ClassNotFoundException e) { e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates. } cpds.setUrl("jdbc:mysql://localhost:3306/test_stackoverflow"); cpds.setUser("root"); cpds.setPassword("root"); SharedPoolDataSource tds = new SharedPoolDataSource(); tds.setConnectionPoolDataSource(cpds); tds.setMaxActive(10); tds.setMaxWait(50); ds = tds; } public static Connection getConnection() throws SQLException { return ds.getConnection(); } } 

username and password must be changed to your db user / password

 import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class MainClass { public static void main(String[] args) { Connection connection = null; Statement statement = null; ResultSet resultSet = null; try { connection = Pool.getConnection(); // Do work with connection statement = connection.createStatement(); String selectEmployeesSQL = "select * from test_table"; resultSet = statement.executeQuery(selectEmployeesSQL); while (resultSet.next()) { printTestTable(resultSet); } } catch (Exception e) { e.printStackTrace(); } finally { if (resultSet != null) { try { resultSet.close(); } catch (SQLException e) { } // nothing we can do } if (statement != null) { try { statement.close(); } catch (SQLException e) { } // nothing we can do } if (connection != null) { try { connection.close(); } catch (SQLException e) { } // nothing we can do } } } private static void printTestTable(ResultSet resultSet) throws SQLException { System.out.print(resultSet.getInt("idtest_table")+", "); System.out.print(resultSet.getString("test_field")); } } 

Just run the main method and you will see the printed test values ​​for the console !!!

Answer 2

You can use an instance of DriverAdapterCPDS . This will need to add two libraries: Apache Commons Pool and Apache Commons DBCP . This is very useful when the driver used does not include the connection pool implementation.

You can find an example at http://massapi.com/class/dr/DriverAdapterCPDS.html