假設Tom和Jerry利用Java UDP進行聊天

1-1 假設Tom和Jerry利用Java UDP進行聊天，請爲他們編寫程序。具體以下：
（1）、Tom和Jerry聊天的雙方都應該具備發送端和接收端；
（2）、利用DatagramSocket與DatagramPacket；
（3）、實現 java.lang.Runnable類，重寫 run()方法。

Jerry代碼：

public class UDPSocket_Jerry { 
   public class UDPSocket_Jerry { 
    public static void main(String[] args) { 
        //分別啓動發信息線程和收消息線程
        Thread thread1 = new Thread(new UDPSocketClientthread());
        Thread thread2 = new Thread(new UDPSocketServerthread());
        thread1.start();
        thread2.start();
    }
}

public class UDPSocketClientthread implements Runnable { 
    DatagramSocket datagramSocket;

    { 
        try { 
            datagramSocket = new DatagramSocket(8081);
        } catch (SocketException e) { 
            e.printStackTrace();
        }
    }

    byte[] ibuf = new byte[1024];
    DatagramPacket datagramPacket = new DatagramPacket(ibuf, ibuf.length);


    @Override
    public void run() { 
        while (true) { 
            try { 
                datagramSocket.receive(datagramPacket);
            } catch (IOException e) { 
                e.printStackTrace();
            }
            System.out.println("Tom：" + new String(datagramPacket.getData(), 0, datagramPacket.getLength()));
        }
    }
}

import java.io.IOException;
import java.net.*;
import java.util.Scanner;

public class UDPSocketServerthread implements Runnable { 
    byte[] ibuf = new byte[1024];
    String message;
    Scanner scanner = new Scanner(System.in);
    DatagramPacket datagramPacket;

    { 
        try { 
            datagramPacket = new DatagramPacket(ibuf, ibuf.length, InetAddress.getByName("127.0.0.1"), 2020);
        } catch (UnknownHostException e) { 
            e.printStackTrace();
        }
    }

    DatagramSocket ds;

    { 
        try { 
            ds = new DatagramSocket(8080, InetAddress.getByName("127.0.0.1"));
        } catch (SocketException | UnknownHostException e) { 
            e.printStackTrace();
        }
    }

    @Override
    public void run() { 
        while (true) { 
            message = scanner.nextLine();
            datagramPacket.setData(message.getBytes());
            try { 
                assert ds != null;
                ds.send(datagramPacket);
            } catch (IOException e) { 
                e.printStackTrace();
            }
        }
    }
}

Tom代碼:

public class UDPSocket_Tom { 
    public static void main(String[] args) { 
        Thread thread1 = new Thread(new UDPSocketClientthread());
        Thread thread2 = new Thread(new UDPSocketServerthread());
        thread1.start();
        thread2.start();
    }
}

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

public class UDPSocketClientthread implements Runnable{ 
        DatagramSocket datagramSocket;
    { 
        try { 
            datagramSocket = new DatagramSocket(2020);
        } catch (SocketException e) { 
            e.printStackTrace();
        }
    }
        byte[] ibuf = new byte[1024];
        DatagramPacket datagramPacket = new DatagramPacket(ibuf, ibuf.length);


    @Override
    public void run() { 
        while(true){ 
            try { 
                datagramSocket.receive(datagramPacket);
            } catch (IOException e) { 
                e.printStackTrace();
            }
            System.out.println("Jerry："+new String(datagramPacket.getData(),0,datagramPacket.getLength()));
        }
    }
}

import java.io.IOException;
import java.net.*;
import java.util.Scanner;

public class UDPSocketServerthread implements Runnable{ 
    byte[] ibuf = new byte[1024];
    String message;
    Scanner scanner = new Scanner(System.in);
    DatagramPacket datagramPacket;

    { 
        try { 
            datagramPacket = new DatagramPacket(ibuf, ibuf.length, InetAddress.getByName("127.0.0.1"), 8081);
        } catch (UnknownHostException e) { 
            e.printStackTrace();
        }
    }
    DatagramSocket ds;
    { 
        try { 
            ds = new DatagramSocket(8083, InetAddress.getByName("127.0.0.1"));
        } catch (SocketException | UnknownHostException e) { 
            e.printStackTrace();
        }
    }

    @Override
    public void run() { 
        while (true) { 
            message = scanner.nextLine();
            datagramPacket.setData(message.getBytes());
            try { 
                assert ds != null;
                ds.send(datagramPacket);
            } catch (IOException e) { 
                e.printStackTrace();
            }
        }
    }
}

代碼運行截圖（用兩個終端開啓）