package guestbook;import javax.sql.DataSource;import java.sql.*;import org.apache.commons.dbcp.BasicDataSource;public class LinkDB {private static DataSource dataSource = null;private static DataSource startupDataSource(String DriverName,String URL,String username,String password) {      BasicDataSource ds = new BasicDataSource();      ds.setDriverClassName(DriverName);      ds.setUsername(username);      ds.setPassword(password);      ds.setUrl(URL);      ds.setMaxActive(100);      ds.setMaxIdle(30);      ds.setMaxWait(10000);      return ds;}public static void setDB(String DriverName,String URL,String username,String password){      dataSource=startupDataSource(DriverName,URL,username,password);}public static DataSource getDB(){      return dataSource;}public static void shutdownDataSource(DataSource ds)throws SQLException {    BasicDataSource bds = (BasicDataSource)ds;    bds.close();}}