java - 如何从DB和JTable中删除选定的行？

Question

在此代码中，它只是从 JTable 中删除行，我想从数据库中删除当运行它时，它会从 JTable 中删除并出现错误:java.lang.ArrayIndexOutOfBoundsException: 2 >= 2 但不从数据库中删除如何解决这个问题？

    private final JPanel panel_09 = new JPanel();
    JScrollPane scrollPane_09 = new JScrollPane();
    final DefaultTableModel TableModel09 = new DefaultTableModel(new String[]{"Picture", "Item", "Price", "After Discount"}, 0);
    final JTable table_09 = new JTable(TableModel09);
    JButton btnNewButton_09 = new JButton("Delete Item");

    btnNewButton_09.addActionListener ( new ActionListener() {


    public void actionPerformed(ActionEvent arg0) {
        try {
            int selectedPlanet = table_09.getSelectedRow();
            TableModel09.removeRow((int) selectedPlanet);
            Object desc = table_09.getModel().getValueAt(selectedPlanet, 4);
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/login", "root", "123");
            String query = "delete from flyer_item where discount=desc";
            java.sql.PreparedStatement ps = conn.prepareStatement(query);
            ps.setString(1, (String) desc);
            ps.executeUpdate();

        } catch (Exception ex) {
            System.err.println(ex);
        }

    }
}
);

Answer 1

在获得 desc 之前，您已从模型中删除了对象:

int selectedPlanet = table_09.getSelectedRow();//<<--this will equal 2

TableModel09.removeRow((int) selectedPlanet);//<<----remove 2

那么现在

Object desc = table_09.getModel().getValueAt(selectedPlanet, 4);
//when you try to `getValueAt(2,4)` you get this error 
//"java.lang.ArrayIndexOutOfBoundsException: 2 >= 2"

为了避免此问题，您必须在删除行之前获取对象:

int selectedPlanet = table_09.getSelectedRow();
Object desc = table_09.getModel().getValueAt(selectedPlanet, 4);
TableModel09.removeRow((int) selectedPlanet);

<小时/>

然后，你会得到另一个 SQL 错误，因为要将参数设置为PreparedStatement，你必须使用 ? :

String query="delete from flyer_item where discount = ?";
//----------------------------------------------------^
java.sql.PreparedStatement ps = conn.prepareStatement(query);
ps.setString(1,(String) desc);