如何将JComboBox数据的选定项提取到Swing文本字段中？

Question

I have a table in my H2 database.

item_name | sac_hsn | price | Tax

And I have JTextfield fields for hsn_code and price .

Now what I want to do is when I select item_name from JComboBox then data of hsn_code and price of that item should also be fetch in the text fields.

I have done this, but it's not working:-

When I run the code then in combo box it doesn't show any item. It was blank.

Connection connection = null;
ResultSet rs;

public void commonMethodForSt(String query) {
    try {
        Statement st = connection.createStatement();
        rs = st.executeQuery(query);

    } catch (Exception e) {
        // TODO Auto-generated catch block
    }   
}

Then..

public void populateItemNameAndDetails() {
    try {
        Class.forName("org.h2.Driver");
        con = 
DriverManager.getConnection("jdbc:h2:C:/SimpleGST/GST","sa","");
        String pname = itemcombo.getSelectedItem().toString();
        commonMethodForSt("select * from additems where item_name='"+pname+"'");
        if(rs.next()) {
//              System.out.print(set_com);
            sachsntext.setText(rs.getString("sac_hsn"));
            pricetext.setText(rs.getString("price"));
            taxtext.setText(rs.getString("TAX_RATE"));
        }
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

After that I set an ActionListener in the combo box and called the method in it.

 itemcombo = new JComboBox();
    itemcombo.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {

               populateItemNameAndDetails();

        }
    });

Answer 1

Okay, I solved that by creating a method that only populates data into comboBox.

public void populateItemCombo() {
    con = DriverManager.getConnection("jdbc:h2:C:/SimpleGST/GST", "sa", "");
    itemcombo.addItem(" ");
    commonMethodForSt("select * from additems");
    while (rs.next()) {
        itemcombo.addItem(rs.getString("item_name"));
    }
}

and call the method.

and the codes that i asked as question are remain same.