How to set the value of specific cell in JTable?

Question

I just want to know how to update specific cell in JTable,

like if I want to set the cell(1,1) to have the value of Test Value.

my code goes like this but does not work for me:

String s = "Test Value";
tableName.setValueAt((Object)s, 1, 1);

Answer 1

You may be looking to use the DefaultTableModel#setValueAt()

DefaultTableModel model = (DefaultTableModel)tableName.getModel();

model.setValueAt(s, 1, 1);

You first need to specify the table with the DefaultTableModel

 DefaultTableModel model = new DefaultTableModel(data, cols);
 JTable table = new JTable(model);

---

You can run this example to see

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;

public class TestTable {
    String[] cols = {"Col 1", "Col2"};
    String[][] data = {{"Hello", "World"},{"Hello", "World"}};
    DefaultTableModel model = new DefaultTableModel(data, cols);
    JTable table = new JTable(model);
    JButton button = new JButton("Set Value at 1, 1");
    JTextField text = new JTextField(20);

    public TestTable() {
        JPanel panel = new JPanel(new BorderLayout());
        panel.add(table, BorderLayout.NORTH);
        panel.add(text, BorderLayout.CENTER);
        panel.add(button, BorderLayout.SOUTH);

        button.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                String value = text.getText();
                model.setValueAt(value, 1, 1);
            }
        });

        JFrame frame = new JFrame();
        frame.add(panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.pack();
        frame.setVisible(true);

    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
               new TestTable();
            }
        });
    }
}

---

EDIT Using Product class.

"I created a class Products with 8 fields, What I want to do is populate the data in ArrayList to my table using loop"

You want to add rows dynamically by using .addRow. You need to get each field from each Product and make it a row. Then add that row like this. Note: You should use getters but for brevity, I didn't.

for (Product p : list) {
    String data1 = p.field1;
    int data2 = p.field2;
    int data3 = p.field3;
    int data4 = p.field4;
    int data5 = p.field5;
    int data6 = p.field6;
    int data7 = p.field7;
    int data8 = p.field8;

    Object[] row = {data1, data2, data3, data4, data5, data6, data7, data8};
    model.addRow(row);

}

---

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;

public class TestTable {
    String[] cols = {"Col 1", "Col 2", "Col 3", "Col 4", "Col 5", "Col 6", "COl 7", "Col 8"};
    DefaultTableModel model = new DefaultTableModel(cols, 0);
    JTable table = new JTable(model);
    JButton button = new JButton("Set Table");
    List<Product> list;

    public TestTable() {
        JPanel panel = new JPanel(new BorderLayout());
        panel.add(new JScrollPane(table), BorderLayout.CENTER);
        panel.add(button, BorderLayout.SOUTH);

        list = getOneRow();

        button.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                for (Product p : list) {
                    String data1 = p.field1;
                    int data2 = p.field2;
                    int data3 = p.field3;
                    int data4 = p.field4;
                    int data5 = p.field5;
                    int data6 = p.field6;
                    int data7 = p.field7;
                    int data8 = p.field8;

                    Object[] row = {data1, data2, data3, data4, data5, data6, data7, data8};
                    model.addRow(row);

                }
            }
        });

        JFrame frame = new JFrame();
        frame.add(panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public List<Product> getOneRow() {
        List<Product> list = new ArrayList<>();
        list.add(new Product("Product 1", 1, 2, 3, 4, 5, 6, 7));
        list.add(new Product("Product 2", 1, 2, 3, 4, 5, 6, 7));
        list.add(new Product("Product 3", 1, 2, 3, 4, 5, 6, 7));
        list.add(new Product("Product 4", 1, 2, 3, 4, 5, 6, 7));


        return list;
    }


    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
               new TestTable();
            }
        });
    }
}

class Product {
    String field1;
    int field2;
    int field3;
    int field4;
    int field5;
    int field6;
    int field7;
    int field8;

    public Product(String s, int f2, int f3, int f4, int f5, int f6, int f7, int f8) {
        field1 = s;
        field2 = f2;
        field3 = f3;
        field4 = f4;
        field5 = f5;
        field6 = f6;
        field7 = f7;
        field8 = f8;

    }  
}