chatapp.java

这是一个小型的聊天系统

package chat2; 
import java.net.*; 
import java.io.*; 
import javax.swing.UIManager; 
import java.awt.*;
//package chat2; 
//import java.net.*; 
//import java.io.*; 
//import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 
import java.lang.*; 
 class ChatApp { 
	boolean packFrame = false; 
	public ChatApp() { 
	ChatFrame frame = new ChatFrame(); 
	if (packFrame) { 
						frame.pack(); 
	} 
	else { 
			frame.validate(); 
	} 
//放置窗体在屏幕中央 
	Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); 
	Dimension frameSize = frame.getSize(); 
	if (frameSize.height > screenSize.height) { 
			frameSize.height = screenSize.height; 
	} 
	if (frameSize.width > screenSize.width) { 
		frameSize.width = screenSize.width; 
	} 
	frame.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2); 
	frame.setVisible(true); 
	frame.waitforpackets(); 
	} 
	public class ChatFrame extends JFrame { 
	JPanel contentPane; 
	Label label1 = new Label();//发送消息 
	Label label2 = new Label();//输入ip 
	Label label3 = new Label();//输入端口标签 
	Label label4 = new Label();//输出端口标签 
	TextField textField1 = new TextField();//输入ip 
	TextField textField2 = new TextField();//发送消息 
	TextField textField3 = new TextField();//获得输入端口 
	TextField textField4 = new TextField();//获得输出端口 
	Button button1 = new Button();//发送消息 
	Button button2 = new Button();//建立连接 
	TextArea textArea1 = new TextArea(); 
	boolean online = false; 
	int portIn = 5000;//输入端口 
	int portOut = 5001;//输出端口 
	DatagramPacket sendpacket,receivepacket;//声明发送和接收数据包 
	DatagramSocket sendsocket,receivesocket;//声明发送和接收DatagramSocket 
	public ChatFrame() { 
		enableEvents(AWTEvent.WINDOW_EVENT_MASK); 
		try { 
			toInit(); 
		} 
		catch(Exception e) { 
			e.printStackTrace(); 
		} 
} 

private void toInit() throws Exception { 
contentPane = (JPanel) this.getContentPane(); 
label1.setText("发送信息："); 
label1.setBounds(new Rectangle(13, 100, 60, 21)); 
contentPane.setLayout(null); 
this.setSize(new Dimension(363, 320)); 
this.setTitle("二人聊天室"); 
label2.setText("输入对方IP地址："); 
label2.setBounds(new Rectangle(12, 19, 109, 23)); 
label3.setText("输入端口："); 
label3.setBounds(new Rectangle(12,58,55,22)); 
label4.setText("输出端口："); 
label4.setBounds(new Rectangle(180,58,55,22)); 
textField3.setText("5000"); 
textField4.setText("5001"); 
textField2.setText("210.77.26.60"); 

button1.setLabel("发送"); 
button1.setBounds(new Rectangle(280, 100, 59, 21)); 
button1.addActionListener(new java.awt.event.ActionListener() { 
public void actionPerformed(ActionEvent e) { 
button1_actionPerformed(e); 
} 
}); 
button2.setLabel("连接"); 
button2.setBounds(new Rectangle(280, 20, 59, 21)); 
button2.addActionListener(new java.awt.event.ActionListener() { 
public void actionPerformed(ActionEvent e) { 
button2_actionPerformed(e); 
} 
}); 

textField4.setBounds(new Rectangle(240,58,90,22)); 
textField3.setBounds(new Rectangle(70,58,90,22)); 
textField2.setBounds(new Rectangle(123, 20, 120, 19)); 
textField1.setBounds(new Rectangle(76, 100, 190, 19)); 
textArea1.setBounds(new Rectangle(11, 140, 333, 134)); 
textArea1.setEditable(false); 
contentPane.add(label4, null); 
contentPane.add(label3, null); 
contentPane.add(label2, null); 
contentPane.add(label1, null); 
contentPane.add(textField1, null); 
contentPane.add(textField2, null); 
contentPane.add(textField3, null); 
contentPane.add(textField4, null); 
contentPane.add(textArea1, null); 
contentPane.add(button1, null); 
contentPane.add(button2,null); 

try { 
sendsocket=new DatagramSocket(5001);//实例化DatagramSocket类作为输出端 
receivesocket=new DatagramSocket(5000);//实例化DatagramSocket类作为输入端 
online = !(sendsocket.isClosed()); 
} 
catch(SocketException se){//异常捕获 
se.printStackTrace() ; 
System.exit(0); 
} 
} 

protected void processWindowEvent(WindowEvent e) { 
super.processWindowEvent(e); 
if (e.getID() == WindowEvent.WINDOW_CLOSING) { 
System.exit(0); 
} 
} 
public void waitforpackets(){//检测并接受对方发来的消息 
while(true){ 
try{ 
byte[]array=new byte[100]; 
receivepacket=new DatagramPacket(array,array.length ); 
receivesocket.receive(receivepacket);//接收 
textArea1.append("\nfrom "+receivepacket.getAddress() +":"+receivepacket.getPort()+" get:"); 
byte data[]=receivepacket.getData() ; 
String received=new String(data,0); 
textArea1.append(received); 
} 
catch (IOException se){ 
se.printStackTrace() ; 
} 
} 
} 

void button2_actionPerformed(ActionEvent e){//和对方建立连接 

String str2 = new String(); 
String str3 = new String(); 
str2 = textField3.getText(); 
str3 = textField4.getText(); 

if(str2.compareTo("")!=0&&str3.compareTo("")!=0){ 

portIn = (int) Integer.parseInt(str2); 
portOut = (int) Integer.parseInt(str3); 


if(online){ 
sendsocket.close(); 
receivesocket.close(); 
textArea1.append("\n formal connection closed"); 
} 

try { 
textArea1.append("\n building a connection use the port defined..."); 
sendsocket=new DatagramSocket(portOut); 
receivesocket=new DatagramSocket(portIn); 
textArea1.append("\n connection builded."); 
} 
catch(SocketException se){ 
se.printStackTrace() ; 
System.exit(0); 
} 
online = !(sendsocket.isClosed()); 
} 


else 
textArea1.append("\nplease input ports and IP"); 

} 

void button1_actionPerformed(ActionEvent e) {//发送消息到对方 


String str=textField2.getText(); 
if(online){ 
if(str.compareTo("")!=0 ){ 


try { 


textArea1.append("\nto "+textField2.getText() +":"+portOut+" say: "+textField1.getText() ); 
String s=textField1.getText() ; 
byte data[]=new byte[100]; 
s.getBytes(0,s.length() ,data,0); 
sendpacket=new DatagramPacket(data,s.length() ,InetAddress.getByName(textField2.getText()),portOut); 
sendsocket.send(sendpacket); 
} 
catch(IOException exc){ 
exc.printStackTrace() ; 
} 

} 

} 
else textArea1.append("\nplease build a connection first!"); 
} 
} 
	public static void main(String[] args) { 
	try { 
		UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); 
	} 
	catch(Exception e) { 
		e.printStackTrace(); 
	} 
	new ChatApp(); 
	} 
 




}