import java.util.*;import java.awt.*;import java.net.*;import java.text.*;import java.awt.event.*;import javax.swing.*;import javax.swing.event.*;/** * Description: * <br/>Copyright (C), 2005-2008, Yeeku.H.Lee * <br/>This program is protected by copyright laws. * <br/>Program Name: * <br/>Date: * @author  Yeeku.H.Lee kongyeeku@163.com * @version  1.0 */public class LanChat extends JFrame{	private DefaultListModel listModel = new DefaultListModel();	//定義一個JList對象	private JList friendsList = new JList(listModel);	//定義一個用于格式化日期的格式器	private DateFormat formatter = DateFormat.getDateTimeInstance(); 	public LanChat()	{		super("局域網聊天");		//設置該JList使用ImageCellRenderer作為單元格繪制器		friendsList.setCellRenderer(new ImageCellRenderer()); 		listModel.addElement(new UserInfo("all" , "所有人" , null , -2000));		friendsList.addMouseListener(new ChangeMusicListener());		add(new JScrollPane(friendsList));		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);		setBounds(2, 2, 160 , 600);	}	//向用戶列表中添加用戶	public void addUser(UserInfo user)	{		listModel.addElement(user);	}	//從用戶列表中刪除用戶	public void removeUser(int pos)	{		listModel.removeElementAt(pos);	}	//根據地址來查詢用戶	public UserInfo getUserBySocketAddress(SocketAddress address)	{		for (int i = 1 ; i < getUserNum() ; i++)		{			UserInfo user = getUser(i);			if (user.getAddress() != null && 				user.getAddress().equals(address))			{				return user;			}		}		return null;	}	//—————————下面兩個方法是對ListModel的包裝—————————	//獲取該聊天窗口的用戶數量	public int getUserNum()	{		return listModel.size();	}	//獲取指定位置的用戶	public UserInfo getUser(int pos)	{		return (UserInfo)listModel.elementAt(pos);	}	//實現JList上的鼠標雙擊監聽器	class ChangeMusicListener extends MouseAdapter	{		public void mouseClicked(MouseEvent e)		{			//如果鼠標的擊鍵次數大于2			if (e.getClickCount() >= 2)			{				//取出鼠標雙擊時選中的列表項				UserInfo user = (UserInfo)friendsList.getSelectedValue();				//如果該列表項對應用戶的交談窗口為null				if (user.getChatFrame() == null)				{					//為該用戶創建一個交談窗口，并讓該用戶引用該窗口					user.setChatFrame(new ChatFrame(null , user));				}				//如果該用戶的窗口沒有顯示，則讓該用戶的窗口顯示出來				if (!user.getChatFrame().isShowing())				{					user.getChatFrame().setVisible(true);				}			}		}	}	/**	 * 處理網絡數據報，該方法將根據聊天信息得到聊天者，	 * 并將信息顯示在聊天對話框中。	 * @param packet 需要處理的數據報	 * @param single 該信息是否為私聊信息	 */	public void processMsg(DatagramPacket packet , boolean single)	{		//獲取該發送該數據報的SocketAddress		InetSocketAddress srcAddress = (InetSocketAddress)packet.getSocketAddress();		//如果是私聊信息，則該Packet獲取的是DatagramSocket的地址，將端口減1才是		//對應的MulticastSocket的地址		if (single)		{			srcAddress = new InetSocketAddress(srcAddress.getHostName(),				srcAddress.getPort() - 1);		}		UserInfo srcUser = getUserBySocketAddress(srcAddress);		if (srcUser != null)		{			//確定消息將要顯示到哪個用戶對應窗口上。			UserInfo alertUser = single ? srcUser : getUser(0);			//如果該用戶對應的窗口為空，顯示該窗口			if (alertUser.getChatFrame() == null)			{				alertUser.setChatFrame(new ChatFrame(null , alertUser));			}			//定義添加的提示信息			String tipMsg = single ? "對您說：" : "對大家說：";			//顯示提示信息			alertUser.getChatFrame().addString(srcUser.getName() + tipMsg				+ "......................(" + formatter.format(new Date()) + ")\n"				+ new String(packet.getData() , 0 , packet.getLength()) + "\n");			if (!alertUser.getChatFrame().isShowing())			{				alertUser.getChatFrame().setVisible(true);			}		}	}	//主方法，程序的入口	public static void main(String[] args) 	{		LanChat lc = new LanChat();		new LoginFrame(lc , "請輸入用戶名、頭像后登陸");	}}//定義用于改變JList列表項外觀的類class ImageCellRenderer extends JPanel implements ListCellRenderer{	private ImageIcon icon;	private String name;	//定義繪制單元格時的背景色	private Color background;	//定義繪制單元格時的前景色	private Color foreground;	public Component getListCellRendererComponent(JList list, Object value, int index, 	  boolean isSelected, boolean cellHasFocus)	{		UserInfo userInfo = (UserInfo)value;		icon = new ImageIcon("ico/" + userInfo.getIcon() + ".gif");		name = userInfo.getName();		background = isSelected ? list.getSelectionBackground() : list.getBackground();		foreground = isSelected ? list.getSelectionForeground() : list.getForeground();		//返回該JPanel對象作為單元格繪制器		return this;	}	//重寫paintComponent方法，改變JPanel的外觀	public void paintComponent(Graphics g)	{		int imageWidth = icon.getImage().getWidth(null);		int imageHeight = icon.getImage().getHeight(null);		g.setColor(background);		g.fillRect(0, 0, getWidth(), getHeight());		g.setColor(foreground);		//繪制好友圖標		g.drawImage(icon.getImage() , getWidth() / 2 - imageWidth / 2 , 10 , null);		g.setFont(new Font("SansSerif" , Font.BOLD , 18));		//繪制好友用戶名		g.drawString(name, getWidth() / 2 - name.length() * 10 , imageHeight + 30 );	}	//通過該方法來設置該ImageCellRenderer的最佳大小	public Dimension getPreferredSize()	{  		return new Dimension(60, 80);	}}