import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.ConnectionPoolDataSource;
import javax.sql.PooledConnection;
public class PooledConnectionExample {
public static void main(String[] args) {
Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;
try {
connection = getConnection();
statement = connection.createStatement();
String selectEmployeesSQL = "SELECT * FROM employees";
resultSet = statement.executeQuery(selectEmployeesSQL);
while (resultSet.next()) {
printEmployee(resultSet);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
closeAll(resultSet, statement, connection);
}
}
//Obtain connection from pool
private static Connection getConnection() throws NamingException, SQLException {
InitialContext initCtx = createContext();
String jndiName = "HrDS";
ConnectionPoolDataSource dataSource = (ConnectionPoolDataSource) initCtx.lookup(jndiName);
PooledConnection pooledConnection = dataSource.getPooledConnection();
return pooledConnection.getConnection();
}
private static InitialContext createContext() throws NamingException {
Properties env = new Properties();
env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.rmi.registry.RegistryContextFactory");
env.put(Context.PROVIDER_URL, "rmi://localhost:1099");
InitialContext context = new InitialContext(env);
return context;
}
private static void printEmployee(ResultSet resultSet) throws SQLException {
System.out.print(resultSet.getInt("employee_id"));
System.out.print(", ");
System.out.print(resultSet.getString("last_name"));
System.out.print(", ");
System.out.print(resultSet.getString("first_name"));
System.out.print(", ");
System.out.println(resultSet.getString("email"));
}
private static void closeAll(ResultSet resultSet, Statement statement, Connection connection) {
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
}
}
}