java面试题之----UDP聊天程序

</pre><h2>通过键盘录入获取要发送的信息。将发送和接收分别封装到两个线程中。</h2><pre name="code" class="java">

package cn.hncu.UDP;

<span style="font-size:32px;color:#ff0000;">//发送方</span>import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.SocketException;public class SendDemo {public static void main(String[] args) {try {DatagramSocket ds = new DatagramSocket(9999);String info="湖南城市学院,Socket通信信息!";byte buf[] = info.getBytes();//用默认码表//DatagramPacket类中，有ip地址的构造方法是用来创建发送数据包的DatagramPacket dp = new DatagramPacket(buf, buf.length, InetAddress.getByName("192.168.1.5"),10000 );//注意，IP和端口都是接收方的ds.send(dp);ds.close();} catch (Exception e) {e.printStackTrace();}}}

<span style="font-size:32px;color:#ff0000;">//接收方</span>

<pre name="code" class="java"><span style="font-size:10px;"><span style="color:#ff0000;">package cn.hncu.UDP;</span>import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.SocketException;public class ReceiveDemo {public static void main(String[] args) {try {DatagramSocket ds = new DatagramSocket(10000);//把数据接收到dp中byte buf[] = new byte[1024];//DatagramPacket类中，没有ip地址的构造方法是用来创建接收数据包的DatagramPacket dp = new DatagramPacket(buf, buf.length);ds.receive(dp);//接收之后，所有的数据都在dp里面//从dp中解析出我们想要的信息//获取ipString ip = dp.getAddress().getHostAddress();int port = dp.getPort();//端口byte data[] = dp.getData();//对方发送的数据String info = new String(data);System.out.println(ip+":"+port+"----"+info);} catch (Exception e) {e.printStackTrace();}}}</span><span style="font-size:32px;"></span>

<span style="font-size:32px;color: rgb(255, 0, 0);">//运行放1</span>

<span style="font-size:32px;color: rgb(255, 0, 0);"></span>

<span style="font-size:10px;">package cn.hncu.UDP;//11111import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.UnknownHostException;public class UDPChat {public static void main(String[] args) {try {DatagramSocket send = new DatagramSocket(10001);DatagramSocket receive = new DatagramSocket(10002);new Thread(new Send(send)).start();new Thread(new Receive(receive)).start();} catch (Exception e) {e.printStackTrace();}}}class Send implements Runnable {private DatagramSocket ds;public Send(DatagramSocket send) {this.ds = send;}@Overridepublic void run() {try {BufferedReader br = new BufferedReader(new InputStreamReader(System.in));String line = null;while ((line = br.readLine()) != null) {byte buf[] = line.getBytes();// 要用接收方的ip和接收端口DatagramPacket dp = new DatagramPacket(buf, buf.length,InetAddress.getByName("192.168.1.5"), 10004);ds.send(dp);if ("over".equals(line)) {break;}}ds.close();} catch (UnknownHostException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}}}class Receive implements Runnable {private DatagramSocket ds;public Receive(DatagramSocket receive) {this.ds = receive;}@Overridepublic void run() {try {byte buf[] = new byte[1024];// 大小够存储一行就可以while (true) {// 接收数据DatagramPacket dp = new DatagramPacket(buf, buf.length);ds.receive(dp);// 解析数据String ip = dp.getAddress().getHostAddress();String info = new String(dp.getData(), 0, dp.getLength());System.out.println(ip + "说:" + info);if ("over".equals(info)) {System.out.println(ip + "离开聊天室...."); break;}}} catch (IOException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}}}</span>

//运行方2

<pre name="code" class="java"><span style="font-size:10px;">package cn.hncu.UDP.chat2;//22222import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.SocketException;import java.net.UnknownHostException;public class UdpChat {public static void main(String[] args) {try {DatagramSocket send = new DatagramSocket(10003);DatagramSocket receive = new DatagramSocket(10004);new Thread(new Send(send) ).start();new Thread(new Receive(receive)).start();} catch (Exception e) {e.printStackTrace();}}}class Send implements Runnable{private DatagramSocket ds;public Send(DatagramSocket send) {this.ds = send;}@Overridepublic void run() {try {BufferedReader br = new BufferedReader(new InputStreamReader(System.in));String line = null;while( (line=br.readLine())!=null ){byte buf[] = line.getBytes();//要用接收方的ip和接收端口DatagramPacket dp = new DatagramPacket(buf, buf.length, InetAddress.getByName("192.168.1.5"), 10002);ds.send(dp);if("over".equals(line)){break;}}ds.close();} catch (UnknownHostException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}}}class Receive implements Runnable{private DatagramSocket ds;public Receive(DatagramSocket receive) {this.ds = receive;}@Overridepublic void run() {try {byte buf[] = new byte[1024];//大小够存储一行就可以while(true){//接收数据DatagramPacket dp = new DatagramPacket(buf, buf.length);ds.receive(dp);//解析数据String ip = dp.getAddress().getHostAddress();String info= new String(dp.getData(),0,dp.getLength());System.out.println(ip+"说:"+info);if("over".equals(info)){System.out.println(ip+"离开聊天室....");break;}}} catch (IOException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}}}</span>