sql查询不会更新JTable

Question

I am currently making an app that allows customers to make accounts and for managers to sign up staff (among other things).

I can get the JTable to display all the accounts but when I click on a button to add a staff member I have to exit the frame and then go back into it to see the update, but I want it to update on the spot.

The next three bits of code are in the DbConnect class and the final one is in the ManageAccount class.

 //This gets the data and creates the tablemodel
 public static DefaultTableModel buildTableModel(ResultSet rs)
        throws SQLException {

    ResultSetMetaData metaData = rs.getMetaData();

    // names of columns
    Vector<String> columnNames = new Vector<String>();
    int columnCount = metaData.getColumnCount();
    for (int column = 1; column <= columnCount; column++) {
        columnNames.add(metaData.getColumnName(column));
    }

    // data of the table
    Vector<Vector<Object>> data = new Vector<Vector<Object>>();
    while (rs.next()) {
        Vector<Object> vector = new Vector<Object>();
        for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
            vector.add(rs.getObject(columnIndex));
        }
        data.add(vector);
    }

    return new DefaultTableModel(data, columnNames);

}

This is the query I use to display the accounts in the JTable

 public JTable ManageAcc2(JTable t) {
    try {
        String query = ("SELECT * FROM staff");
        rt = st.executeQuery(query);

        t = new JTable(buildTableModel(rt));

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

 return t;
}   

This is the query that adds an extra staff member

public void AddStaff(JTable t) {

    try {

        String query = "INSERT INTO staff VALUES('" + NULL + "','" + NULL + "','" + NULL + "','" + NULL + "','" + NULL + "','staff')";
        st.executeUpdate(query);

    } catch (Exception ex) {
        ex.printStackTrace();
    } 
}

Finally this is a separate class where I create the table that contains all the data

public class ManageAccount extends JPanel{

JPanel jNorth = new JPanel();
JPanel jCenter = new JPanel();
JPanel jSouth = new JPanel();
    JTable t = new JTable();

JScrollPane listScroll = new JScrollPane();
    JScrollPane listScroll2 = new JScrollPane();
    JScrollPane listScroll3 = new JScrollPane();
    JButton AddStaff = new JButton("Add Staff");
JButton goBack = new JButton("Back");
    ManagerDashboard md;
    DbConnect dbc = new DbConnect();  

ManageAccount(ManagerDashboard m){
      try{  


            this.md = m;
            this.setPreferredSize(new Dimension(600, 400));
    this.setVisible(true);

    this.setLayout(new BorderLayout());
    this.add(jNorth, BorderLayout.NORTH);
    this.add(jCenter, BorderLayout.CENTER);
    this.add(jSouth, BorderLayout.SOUTH);                       

            listScroll = new JScrollPane(dbc.ManageAcc(t));
            listScroll.setPreferredSize(new Dimension(600, 116));

            listScroll2 = new JScrollPane(dbc.ManageAcc2(t));
            listScroll2.setPreferredSize(new Dimension(600, 116));

    jNorth.setLayout(new BorderLayout());
    jNorth.add(goBack, BorderLayout.WEST);
    goBack.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {

     md.removeManageAccount();

        }
    }); 

            jCenter.add(listScroll);  
            jCenter.add(listScroll2);

            jSouth.setLayout(new FlowLayout());
    jSouth.add(AddStaff, BorderLayout.SOUTH);
            AddStaff.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e){
                dbc.AddStaff(t);

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

}

I have looked at other answers to similar questions but using methods like setModel(), repaint(),etc doesn't seem to work for me.

Thanks in advance

Answer 1

Make the jTable reference the ManageAccount class' field rather than local variable.

In your AddStaff you pass the JTable but use the introduced field instead. After inserting call something like this

    String query = ("SELECT * FROM staff");
    rt = st.executeQuery(query);

    theTableField.setModel(buildTableModel(rt));