Java - 如何关闭SQLite Connection抛出异常？

Question

我见过很多关闭人们在DAO方法中使用finally{}的数据库连接的例子，但在我的例子中，DAO方法（例如：insertUsers（））会抛出它所调用的方法的异常。在这种情况下，我如何关闭我的连接？

我收到“SQLiteException - 数据库被锁定”错误。

这是我的代码：

DAO

public static Connection con = null;
private static boolean hasData = false;

private void getConnection() throws ClassNotFoundException, SQLException {
    Class.forName("org.sqlite.JDBC");
    con = DriverManager.getConnection("jdbc:sqlite:ProjFarmacia.db");
    initialise();
}

private void initialise() throws SQLException {
   if( !hasData ){
       hasData = true;
       Statement state = con.createStatement();
       ResultSet res = state.executeQuery("SELECT name FROM sqlite_master WHERE type='table' AND name='caixa'");
       if(!res.next()){
           Statement state2 = con.createStatement();
           state2.execute("CREATE TABLE caixa(id integer, timestamp integer, valorTotal double,  notas1 integer, notas2 integer,"
                   + " notas5 integer, notas10 integer, notas20 integer"
                   + "notas50 integer, notas100 integer, moedas1 integer, moedas5 integer, moedas10 integer, moedas25 integer"
                   + "moedas50 integer, moedas1R integer, primary key(id));");
       }   
   }
}




public ResultSet getCaixaByDate(long timestamp) throws ClassNotFoundException, SQLException{
    if(con == null){
        getConnection();
    }

    Statement state = con.createStatement();
    ResultSet res = state.executeQuery("SELECT * FROM caixa WHERE timestamp=" + "'" + timestamp + "'" + ";");
    return res;
}


public void createCaixa(Caixa caixa) throws ClassNotFoundException, SQLException{
    if(con == null){
        getConnection();
    }
    PreparedStatement prep = con.prepareStatement("INSERT INTO caixa VALUES(?,?);");
    prep.setLong(1, caixa.getTimestamp());
    prep.setDouble(2, caixa.getValorTotal());
    con.close();
}

主要申请

  try {
        ResultSet rs = caixaDAO.getCaixaByDate(timestamp);

        //If not exists in database
        if(!rs.next()){
            Caixa caixa = new Caixa();
            caixa.setTimestamp(timestamp);
            caixa.setValorTotal(venda.getValorDaVenda());

            //Inserting new Caixa
            caixaDAO.createCaixa(caixa);
        }else{
            System.out.println("Caixa already created!!!");
        }

    } catch (ClassNotFoundException | SQLException ex) {
        Logger.getLogger(VendaMedicamento.class.getName()).log(Level.SEVERE, null, ex);
 }