错误空指针异常

Question

在这里，我想通过单击数据库中已经包含 101 id 处某个名称的按钮在组合框中获取一些数据......

try {
    con = DriverManager.getConnection("jdbc:odbc:nit");
    pst = con.prepareStatement("select name from [Sheet1$] where id = ?");
    pst.setString(1, "101");
    try {
        while (rs.next()) {
            ComboBox1.addItem(rs.getString("name"));
        }
        pst.close();
        con.close();
    } catch (NullPointerException e2) {
        JOptionPane.showMessageDialog(null, "ER:-" + e2);
    }
} catch (Exception e) {
    JOptionPane.showMessageDialog(null, "Error" + e);
}

Answer 1

您尚未声明和初始化变量rs ResultSet类型。您需要执行PreparedStament并将返回分配给rs