java - 从另一个类访问 jtable

Question

我发现了类似的项目，但我就是无法掌握如何做到这一点的概念。我有一个名为 HealthTracker 的类，其中包含一个 JTable。然后我有另一个名为 SQL 的类，它具有所有与 sql 相关的方法。其中一种方法称为 populateTable。我可以执行查询等，但我不知道如何从 SQL 类访问位于 HealthTracker 类中的 JTable。这是我的 SQL 类的代码。

public void populateTable(int qryType){ 
    try{
        DefaultTableModel tblModel = new DefaultTableModel(){
           @Override
           public boolean isCellEditable(int row, int column){
              return false;
           }
        };

        Connection dbconn = SQL.dbConn();
        Statement stmt = dbconn.createStatement();

        String qry = "SELECT * FROM Services";
        ResultSet rs = stmt.executeQuery(qry);

        int numCols = rs.getMetaData().getColumnCount();            
        for (int col = 1; col <= numCols; col++){
            tblModel.addColumn(rs.getMetaData().getColumnLabel(col));
        }

        int row = 0;
        while (rs != null && rs.next()){
            tblModel.addRow(new Object[0]);
            tblModel.setValueAt(rs.getString("ServiceID"), row, 0);
            tblModel.setValueAt(rs.getString("Institution"), row, 1);
            tblModel.setValueAt(rs.getString("Comments"), row, 2);
            row++;
        }   
        rs.close(); 

        // This is the line that gives me the error
        HealthTracker.this.tblMain.setModel(tblModel);

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

这很棒，但是我仍然需要能够从其他类访问该 JTable。当应用程序首次加载以初始化表时，会看到此代码，但用户需要能够过滤数据。因此，我创建了一个过滤器按钮，它显示另一个窗口(SearchRecord.java 类)，用户可以在其中输入参数，然后单击“查找”。单击“查找”按钮后，我将运行查询，并且应该使用新结果重新加载表。也许我的处理方式是错误的？

public class SearchRecord {

    private JFrame frame;
    private JTextField txtInstitution;
    private JTextField txtStartDate;
    private JTextField txtEndDate;

    //  Launch the application
    public static void searchForm() {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    SearchRecord window = new SearchRecord();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    //  Create the application
    public SearchRecord() {
        initialize();
    }

    //  Initialize the contents of the frame
    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 462, 180);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JLabel label = new JLabel("Enter Search Parameters");
        label.setHorizontalAlignment(SwingConstants.CENTER);
        label.setFont(new Font("Tahoma", Font.BOLD, 12));
        label.setBounds(10, 11, 414, 14);
        frame.getContentPane().add(label);

        JLabel lblInstitution = new JLabel("Institution: ");
        lblInstitution.setBounds(10, 47, 85, 14);
        frame.getContentPane().add(lblInstitution);
        lblInstitution.setHorizontalAlignment(SwingConstants.RIGHT);
        lblInstitution.setFont(new Font("Tahoma", Font.BOLD, 12));

        txtInstitution = new JTextField();
        txtInstitution.setBounds(98, 45, 326, 20);
        frame.getContentPane().add(txtInstitution);
        txtInstitution.setColumns(10);

        JLabel lblStartDate = new JLabel("Start Date: ");
        lblStartDate.setBounds(10, 78, 85, 14);
        frame.getContentPane().add(lblStartDate);
        lblStartDate.setHorizontalAlignment(SwingConstants.RIGHT);
        lblStartDate.setFont(new Font("Tahoma", Font.BOLD, 12));

        txtStartDate = new JTextField();
        txtStartDate.setBounds(98, 76, 175, 20);
        frame.getContentPane().add(txtStartDate);
        txtStartDate.setColumns(10);

        JButton button = new JButton("...");
        button.setBounds(283, 76, 25, 23);
        frame.getContentPane().add(button);

        JButton button_1 = new JButton("...");
        button_1.setBounds(283, 106, 25, 23);
        frame.getContentPane().add(button_1);

        JLabel lblEndDate = new JLabel("End Date: ");
        lblEndDate.setBounds(10, 109, 85, 14);
        frame.getContentPane().add(lblEndDate);
        lblEndDate.setHorizontalAlignment(SwingConstants.RIGHT);
        lblEndDate.setFont(new Font("Tahoma", Font.BOLD, 12));

        txtEndDate = new JTextField();
        txtEndDate.setBounds(98, 107, 175, 20);
        frame.getContentPane().add(txtEndDate);
        txtEndDate.setColumns(10);

        JButton btnFind = new JButton("Find");
        btnFind.setFont(new Font("Tahoma", Font.BOLD, 12));
        btnFind.setBounds(354, 106, 70, 23);
        frame.getContentPane().add(btnFind);

        //  Find Records
        btnFind.addActionListener(new ActionListener() 
        {
            public void actionPerformed(ActionEvent e) 
            {
                //  Gather all the fields from form
                String[] fields = new String[3];
                fields[0] = txtInstitution.getText();
                fields[1] = txtStartDate.getText();
                fields[2] = txtEndDate.getText();

                //  Refresh Table w/Filtered Data from DB
                SQL loadTbl = new SQL();
                try{
                    HealthTracker.this.tblMain.setModel(loadTbl.populateTable(0));
                } catch (SQLException e1){
                    e1.printStackTrace();
                }               
            }
        });     
    }
}

Answer 1

让您的 populateTable 方法返回 TableModel 的实例，而不是让它尝试将模型应用到 JTable 的实例

public TableModel populateTable(int qryType) throws SQLException{ 
    DefaultTableModel tblModel = new DefaultTableModel(){
       @Override
       public boolean isCellEditable(int row, int column){
          return false;
       }
    };
    String qry = "SELECT * FROM Services";
    try (Connection dbconn = SQL.dbConn(); 
        Statement stmt = dbconn.createStatement();
        ResultSet rs = stmt.executeQuery(qry)) {

        int numCols = rs.getMetaData().getColumnCount();            
        for (int col = 1; col <= numCols; col++){
            tblModel.addColumn(rs.getMetaData().getColumnLabel(col));
        }

        int row = 0;
        while (rs != null && rs.next()){
            tblModel.addRow(new Object[0]);
            tblModel.setValueAt(rs.getString("ServiceID"), row, 0);
            tblModel.setValueAt(rs.getString("Institution"), row, 1);
            tblModel.setValueAt(rs.getString("Comments"), row, 2);
            row++;
        }   
    }
    return model;
}

这意味着该方法只有一项工作，加载TableModel，仅此而已。这也意味着您可以随时随地以您喜欢的方式调用它