public class Conexao {

  private static Conexao instance = null;
	private final String USERNAME = user;
	private final String PASSWORD = pass;
	private final String CONN_STRING = "jdbc:sqlserver://<ip>:<port>;DatabaseName=<database>";
	private Connection conn = null;

	public static Conexao getInstance() {
		if (instance == null) {
			instance = new Conexao();
		}
		return instance;
	}


	private boolean openConnection()
	{
		try {
			conn = DriverManager.getConnection(CONN_STRING, USERNAME, PASSWORD);
			return true;
		}
		catch (SQLException e) {
			System.err.println(e);
			return false;
		}
	}

	public Connection getConnection()
	{
		if (conn == null) {
			if (openConnection()) {
				System.out.println("Conexão aberta!");
				return conn;
			} else {
				return null;
			}
		}
		System.out.println("Sem necessidade...");
		return conn;
	}

	public void close() {
		System.out.println("Fechando conexão...");
      try {
        conn.close();
        conn = null;
        System.out.println("Conexão fechada!");
      } catch (Exception e) {}
  }

}