login.java

下载的JAVA局域网的聊天程序,请大下们帮我看看 里面有几个问题

import java.awt.*;
import java.awt.event.*;
public class Login implements ActionListener{
	
	Frame jf = new Frame("登录框");
	Panel p1 = new Panel();
	Panel p2 = new Panel();
	Label l1 = new Label("用 户 名 :");
	Label l2 = new Label("服务器IP地址:");
	TextField t1 = new TextField();
	TextField t2 = new TextField();
	Button loginButton=new Button("登录");
	
	public static void main(String[] args)
	{
		new Login(); //启动登陆界面
	}
		
	public Login(){
		p1.setLayout(new GridLayout(2,2));
		p1.add(l1);
		p1.add(t1);
		p1.add(l2);
		p1.add(t2);
		p2.setLayout(new FlowLayout());
		p2.add(loginButton);
		jf.add(p1,"North");
		jf.add(p2);
		jf.setBackground(new Color(220,220,255));
		jf.setSize(250,120);
		jf.setLocation(300,200);
		jf.setVisible(true);
		t2.addActionListener(this);
		loginButton.addActionListener(this);
		jf.addWindowListener(new WindowAdapter()
		{
			public void windowClosing(WindowEvent e)
			{
				System.exit(0);
			}
		});
	}
	
	public void actionPerformed(ActionEvent e)
			{
				if(t1.getText().equals("")  && t2.getText().equals(""))
				{
					System.out.println("请输入用户名和服务器名");
					System.exit(1);
				}
				else if(t2.equals(""))
				{
					System.out.println("请输入你想连接的服务器IP地址");
					System.exit(1);
				}
				else
				{
					ChatClient c=new ChatClient(t1.getText(),t2.getText()); //创建聊天用的面板,并将t1.getText(),t2.getText()做为构造方法的参数
					jf.setVisible(false);
				}
			}
			
			
		
	
}