在GUI JTextArea中显示双数组值

Question

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.text.DecimalFormat;

public class DollarStoreBennettJordan extends JApplet implements ActionListener
  {
    JFrame   frame = new JFrame();

    JLabel     n1  = new JLabel("Enter sales person number(1-4): ");
    JTextField tf1 = new JTextField(5);

    JLabel     n2  = new JLabel("Enter product number(1-5): ");
    JTextField tf2 = new JTextField(5);

    JLabel     n3  = new JLabel("Enter sales amount(0.01-0.99): ");
    JTextField tf3 = new JTextField(5);

    JTextArea  ta  = new JTextArea(8,58);

    JButton    b1  = new JButton("Submit");
    JButton    b2  = new JButton("Clear");

    double[][] sales = {
                       { 0.00, 0.00, 0.00, 0.00, 0.00 },
                       { 0.00, 0.00, 0.00, 0.00, 0.00 },
                       { 0.00, 0.00, 0.00, 0.00, 0.00 },
                       { 0.00, 0.00, 0.00, 0.00, 0.00 }
                       };  
    double[] product_totals = new double [sales.length];
    int total;


  public void init()
  { 
    setLayout(new FlowLayout(FlowLayout.CENTER));

    add(n1);
    add(tf1);
    add(n2);
    add(tf2);
    add(n3);
    add(tf3);
    add(ta);
    add(b1);
    add(b2);
    ta.setEditable(false);
    ta.setFont(new Font("Courier", Font.BOLD, 10));
    b1.addActionListener(this);
    b2.addActionListener(this);
  }

  private boolean emptyFields()
  {
    boolean result;

    if(tf1.getText().equals(""))                   //check tf1       
    {
    result = true;
    tf1.requestFocus();
    showStatus("Please enter a value for salesperson number");
    }

    else
    {
    result = false;
    }

    if(tf2.getText().equals(""))                   //check tf2            
    {
    result = true;
    tf2.requestFocus();
    showStatus("Please enter an item number");
    }

    else
    {
    result = false;
    }

    if(tf3.getText().equals(""))                   //check tf3    
    {
    result = true;
    tf3.requestFocus();
    showStatus("Please enter a valid price");
    }

    else
    {
    result = false;
    }

    return result;
  }

  public void actionPerformed(ActionEvent e)
  {
    showStatus("");

    if (e.getSource() == b2)
    {
    tf1.setText("");
    tf2.setText("");
    tf3.setText("");
    tf1.requestFocus();
    }

    else if (e.getSource() == b1)
    {
    emptyFields();
    drawSummary();
    }
  }

  private void drawSummary()
  {
    ta.setText("");
    DecimalFormat money = new DecimalFormat("0.00");

    for (int r = 0; r < sales.length; r++)
    {
      total = 0;
      for (int c = 0; c < sales[0].length; c++)
      {
        total += sales[r][c];
      }
      product_totals[r] = total;
    } 

    for (int i = 0; i < sales.length; i++)
    {

    }  
  }

  private void drawSeparators(char separator)
  {

  }
}  

嘿那里，我希望有人可以帮助我。我在让数组销售显示在JTextArea中时遇到问题。完成后，applet应该为销售人员，项目和价格获取输入，并使用输入来更新阵列。我还是初学者，所以我不知道如何在文本区域显示数组，然后用输入更新它，从那里去哪里。谢谢，任何帮助表示赞赏。