java单例模式返回数据库连接

import java.sql.Connection;
import java.sql.DriverManager;

public class DBHelper {
	
	private static final String driver = "com.mysql.jdbc.Driver";//数据库驱动
	private static final String url = "jdbc:mysql://localhost:3306/gumysql?useUnicon=true&characterEncoding=UTF-8";
	private static final String username = "root";
	private static final String password = "root";
	
	static
	{
		try 
		{
			Class.forName(driver);
		}
		catch (Exception e)
		{
			
			e.printStackTrace();
		}
	}
	
	private static Connection conn = null;
	//单例模式返回数据库连接
	public static Connection getConnection() throws Exception
	{
		if(conn == null)
		{
			conn = DriverManager.getConnection(url, username, password);
			return conn;
		}
		else
		{
			return conn;
		}
	}
}