小编use*_*005的帖子

我试图找出一种方法来打印到JTextArea而不抛出异常.目前我正在抛出NullPointerException但是在我尝试打印到JTextArea时.我不确定它出错的地方或原因.有人请帮帮我.谢谢.

 import java.awt.EventQueue;
 import java.util.LinkedList;
 import java.util.Queue;
 import java.util.Stack;
 import javax.swing.JFrame;
 import javax.swing.JButton;
 import javax.swing.JLabel;
 import javax.swing.JScrollPane;
 import javax.swing.SwingConstants;
 import javax.swing.JTextField;
 import javax.swing.JScrollBar;
 import java.awt.event.ActionListener;
 import java.awt.event.ActionEvent;
 import javax.swing.JTextArea;

 public class TicketLine {

private JFrame frame;
private JTextArea textArea;

public static void main(String[] args) {

    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                TicketLine window = new TicketLine();
                window.frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

public TicketLine() {
    initialize();
}

/**
 * Initialize the contents …