《Java就業(yè)培訓(xùn)教程》 作者：張孝祥 書(shū)中源碼 
《Java就業(yè)培訓(xùn)教程》P374源碼
發(fā)送程序：UdpSend.java
import java.net.*;
public class UdpSend
{
	public static void main(String [] args) throws Exception
	{
		DatagramSocket ds=new DatagramSocket();
		String str="hello world";
		DatagramPacket dp=new DatagramPacket(str.getBytes(),str.length(),
InetAddress.getByName("192.168.0.213"),3000);
		ds.send(dp);
		ds.close();
	}
}

接收程序:UdpRecv.java
import java.net.*;
public class UdpRecv
{
	public static void main(String [] args) throws Exception
	{
		DatagramSocket	ds=new DatagramSocket(3000);
		byte [] buf=new byte[1024];
		DatagramPacket dp=new DatagramPacket(buf,1024);
		ds.receive(dp);
		String strRecv=new String(dp.getData(),0,dp.getLength()) +
		" from " + dp.getAddress().getHostAddress()+":"+dp.getPort(); 
		System.out.println(strRecv);
		ds.close();
	}
}
《Java就業(yè)培訓(xùn)教程》P378源碼
import java.awt.*;
import java.awt.event.*;
import java.net.*;
public class Chat 
{
	Frame f=new Frame("我的聊天室");
	TextField tfIP=new TextField(15);
	List lst=new List(6);
	DatagramSocket ds;
/*由于DatagramSocket的構(gòu)造函數(shù)聲明可能拋出異常，我們的程序需要用try…catch語(yǔ)句
進(jìn)行異常捕獲處理，所以不能直接在這里調(diào)用DatagramSocket的構(gòu)造函數(shù)對(duì)ds進(jìn)行初始化，
我們需要將ds的初始化放在Chat類的構(gòu)造函數(shù)中去完成。*/
	public Chat()
	{
	        try
	        {
	            ds=new DatagramSocket(3000);
	        }catch(Exception ex){ex.printStackTrace();}
	}
	public static void main(String [] args)
	{
		Chat chat=new Chat();
		chat.init();
	}
	public void init()
	{
		f.setSize(300,300);
		f.add(lst);

		Panel p=new Panel();
		p.setLayout(new BorderLayout());
		p.add("West",tfIP);
		TextField tfData=new TextField(20);
		p.add("East",tfData);
		f.add("South",p);
		f.setVisible(true);
		f.setResizable(false);//限制用戶改變窗口的大小
		
		//增加關(guān)閉窗口的事件處理代碼
		f.addWindowListener(new WindowAdapter()
{
	public void windowClosing(WindowEvent e)
	{
		ds.close();//程序退出時(shí)，關(guān)閉Socket，釋放相關(guān)資源
		f.setVisible(false);
		f.dispose();
		System.exit(0);
	}
});	
		//增加在消息文本框中按下回車(chē)鍵的事件處理代碼
		tfData.addActionListener(new ActionListener()
{
    			public void actionPerformed(ActionEvent e)
    			{
		//取出文本框中的消息字符串，并將其轉(zhuǎn)換成字節(jié)數(shù)組
				byte[] buf;
				buf = e.getActionCommand().getBytes();
	try
	{
		DatagramPacket dp= new DatagramPacket(buf,buf.length,
		InetAddress.getByName(tfIP.getText()),3000);
		ds.send(dp);
}catch(Exception ex){ex.printStackTrace();}
/*上面的Exception的引用變量名不能為e，而是改寫(xiě)成了ex，因?yàn)閑已經(jīng)在
actionPerformed方法中作為形式參數(shù)變量名被定義過(guò)了。*/
            		((TextField)e.getSource()).setText("");
    			}	
});
	}
}
《Java就業(yè)培訓(xùn)教程》P380源碼
import java.awt.*;
import java.awt.event.*;
import java.net.*;
public class Chat 
{
	Frame f=new Frame("我的聊天室");
	TextField tfIP=new TextField(15);
	List lst=new List(6);
	DatagramSocket ds;。
	public Chat()
	{
	        try
	        {
	            ds=new DatagramSocket(3000);
	        }catch(Exception ex){ex.printStackTrace();}
			new Thread(new Runnable()
{
public void run()
    {
    	byte buf[]=new byte[1024];  
        DatagramPacket dp= new DatagramPacket(buf,1024); 
        while(true)
        {
           try
           {
           		ds.receive(dp);
                lst.add(new String(buf,0,dp.getLength())+
":from"+dp.getAddress().getHostAddress(),0);
           }catch(Exception e){e.printStackTrace();}                 
         }
	}
}).start();
	}
	……
}
《Java就業(yè)培訓(xùn)教程》P385源碼
import java.net.*;
import java.io.*;
public class TcpServer
{
	public static void main(String [] args) 
	{
		try
		{
		ServerSocket ss=new ServerSocket(8001);
		Socket s=ss.accept();
		InputStream ips=s.getInputStream();
		OutputStream ops=s.getOutputStream();
		ops.write("welcome to www.it315.org!".getBytes());
		byte [] buf = new byte[1024];
		int len = ips.read(buf);
		System.out.println(new String(buf,0,len));
		ips.close();
		ops.close();
		s.close();
		ss.close();
		}catch(Exception e){e.printStackTrace();}
	}
}
《Java就業(yè)培訓(xùn)教程》P388源碼
import java.net.*;
import java.io.*;
class Servicer implements Runnable
{
	Socket s;
	public Servicer(Socket s)
	{
		this.s = s;
	}
	public void run()
	{
	try
	{
	InputStream ips=s.getInputStream();
	OutputStream ops=s.getOutputStream();
	
	BufferedReader br = new BufferedReader(new InputStreamReader(ips));
	DataOutputStream dos = new DataOutputStream(ops);
	while(true)
	{
		String strWord = br.readLine();
		//System.out.println(strWord +":" + strWord.length());
		if(strWord. equalsIgnoreCase("quit"))
			break;
		String strEcho = (new StringBuffer(strWord).reverse()).toString();
		//dos.writeBytes(strWord +"---->"+ strEcho +"\r\n");
		dos.writeBytes(strWord + "---->"+ strEcho +
	System.getProperty("line.separator"));			}
	br.close();
	//關(guān)閉包裝類，會(huì)自動(dòng)關(guān)閉包裝類中所包裝的底層類。所以不用調(diào)用ips.close()
	dos.close();
	s.close();
	}catch(Exception e){e.printStackTrace();}
	}
}
class TcpServer
{
	public static void main(String [] args)
	{
		try
		{
			ServerSocket ss=new ServerSocket(8001);
			while(true)
			{
				Socket s=ss.accept();
				new Thread(new Servicer(s)).start();
			}
			//ss.close();
		}catch(Exception e){e.printStackTrace();}
	}
}
《Java就業(yè)培訓(xùn)教程》P391源碼
import java.net.*;
import java.io.*;
public class TcpClient
{
	public static void main(String [] args) 
	{
	try
	{
		//Socket s=new Socket(InetAddress.getByName("192.168.0.213"),8001);
		if(args.length < 2)
		{
			System.out.println("Usage:java TcpClient ServerIP ServerPort");
			return;
		}
		Socket s=new Socket(
		InetAddress.getByName(args[0]),Integer.parseInt(args[1]));
		InputStream ips=s.getInputStream();
		OutputStream ops=s.getOutputStream();
		
		BufferedReader brKey = 
		new BufferedReader(new InputStreamReader(System.in));
		DataOutputStream dos = new DataOutputStream(ops);
		BufferedReader brNet = new BufferedReader(new InputStreamReader(ips));

		while(true)
		{
			String strWord = brKey.readLine();
			dos.writeBytes(strWord + System.getProperty("line.separator"));
			if(strWord.equalsIgnoreCase("quit"))
				break;
			else
				System.out.println(brNet.readLine());
		}
		dos.close();
		brNet.close();
		brKey.close();
		s.close();
	}catch(Exception e){e.printStackTrace();}
	}
}