java - 通过java搜索整数类型的数据库字段

Question

我想通过提供凭单编号作为搜索条件来搜索数据库，但凭单编号是整数，因此我无法使用以下代码执行此操作，请为此建议一些其他代码。

  try{
            String sql = "select item_type as 'Item Type', md_by as 'Made By', model as       'Model', selling_price as 'Selling Price', purchase_price as 'Purchase Price', purchase_date as 'Purchase Date', vouch_no as 'Voucher No.', vouch_date as 'Voucher Date', record_no as 'Record No.' from purchase" where vouch_no = ?;
            ps = con.prepareStatement(sql);
            ps.setString(1 , txt_vouchno_p.getText());
            rs = ps.executeQuery();
            Table_p.setModel(DbUtils.resultSetToTableModel(rs));


        }   
        catch(SQLException ex){

                JOptionPane.showMessageDialog(null, "Error: " + ex);

        }
        catch(Exception ex){
            JOptionPane.showMessageDialog(null, "Error: " + ex);
        }

Answer 1

使用 Integer#parseInt 将 txt_vouchno_p.getText() 的值转换为 int并将其相应地传递给您的 PreparedStatement:

ps.setInt(1, Integer.parseInt(txt_vouchno_p.getText()));

---

在你当前的代码中看起来像是一个拼写错误，但是对于大的文字 String，不要害怕将它分成几行，编译器足够聪明，可以将它转换成一个大的 code>String 给你。所以，这一行:

String sql = "select item_type as 'Item Type', md_by as 'Made By', model as       'Model', selling_price as 'Selling Price', purchase_price as 'Purchase Price', purchase_date as 'Purchase Date', vouch_no as 'Voucher No.', vouch_date as 'Voucher Date', record_no as 'Record No.' from purchase" where vouch_no = ?;

应该重写为:

String sql = "select item_type as 'Item Type'"
    + ", md_by as 'Made By'"
    + ", model as 'Model'"
    + ", selling_price as 'Selling Price'"
    + ", purchase_price as 'Purchase Price'"
    + ", purchase_date as 'Purchase Date'"
    + ", vouch_no as 'Voucher No.'"
    + ", vouch_date as 'Voucher Date'"
    + ", record_no as 'Record No.'"
    + " from purchase"
    + " where vouch_no = ?";