Java Swing JTable不可见

Question

I'm having trouble getting my JTable to show up in the Frame. The window opens when I run the program, but it is blank. New to Swing and I'm not sure what I'm doing wrong. Please help!

import javax.swing.*;
import java.awt.*;

public class MatrixGenerator{
    public static void main(String args[]){
        JFrame grid = new JFrame("Exercise14_07");
        grid.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container view = grid.getContentPane();
        int dimension = 10;
        int value;
        String entry;
        String[] columns = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
        Object[][] matrix = new Object[dimension][dimension];
        for(int i = 0; i < dimension; i++){
            for(int j = 0; j < dimension; j++){
                value = (int)Math.floor(Math.random()*2);
                entry = Integer.toString(value);
                matrix[i][j] = entry;
            }
        }

        JTable randomMatrix = new JTable(matrix, columns);
        JScrollPane scrollpane = new JScrollPane(randomMatrix);
        randomMatrix.setFillsViewportHeight(true);
        randomMatrix.setVisible(true);
        grid.setSize(300, 300);
        grid.setVisible(true);
    }
}

Answer 1

JTable randomMatrix = new JTable(matrix, columns);
JScrollPane scrollpane = new JScrollPane(randomMatrix);

// This is very important
grid.add(scrollpane);

randomMatrix.setFillsViewportHeight(true);
grid.setSize(300, 300);
grid.setVisible(true);