</pre>一. UDP协议定义<br style="padding: 0px; margin: 0px; line-height: 1.5em;" /><p>UDP协议的全称是用户数据报，在网络中它与TCP协议一样用于处理数据包。在OSI模型中，在第四层——传输层，处于IP协议的上一层。UDP有不提供数据报分组、组装和不能对数据包的排序的缺点，也就是说，当报文发送之后，是无法得知其是否安全完整到达的。</p><p></p><span style="padding:0px; margin:0px; line-height:1.5em">二. 使用UDP的原因</span><br style="padding:0px; margin:0px; line-height:1.5em" />它不属于连接型协议，因而具有资源消耗小，处理速度快的优点，所以通常音频、视频和普通数据在传送时使用UDP较多，因为它们即使偶尔丢失一两个数据包，也不会对接收结果产生太大影响。比如我们聊天用的ICQ和OICQ就是使用的UDP协议。在选择使用协议的时候，选择UDP必须要谨慎。在网络质量令人不十分满意的环境下，UDP协议数据包丢失会比较严重。<br style="padding:0px; margin:0px; line-height:1.5em" /><br style="padding:0px; margin:0px; line-height:1.5em" /><span style="padding:0px; margin:0px; line-height:1.5em">三. 在Java中使用UDP协议编程的相关类</span><br style="padding:0px; margin:0px; line-height:1.5em" />1. InetAddress<br style="padding:0px; margin:0px; line-height:1.5em" />用于描述和包装一个Internet IP地址。有如下方法返回实例：<br style="padding:0px; margin:0px; line-height:1.5em" />getLocalhost()：返回封装本地地址的实例。<p></p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px">getAllByName(String host)：返回封装Host地址的InetAddress实例数组。</p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px">getByName(String host)：返回一个封装Host地址的实例。其中，Host可以是域名或者是一个合法的IP地址。<br style="padding:0px; margin:0px; line-height:1.5em" />InetAddress.getByAddress(addr)：根据地址串返回InetAddress实例。<br style="padding:0px; margin:0px; line-height:1.5em" />InetAddress.getByAddress(host, addr)：根据主机地符串和地址串返回InetAddress实例。<br style="padding:0px; margin:0px; line-height:1.5em" /><br style="padding:0px; margin:0px; line-height:1.5em" />2. DatagramSocket<br style="padding:0px; margin:0px; line-height:1.5em" />用于接收和发送UDP的Socket实例。该类有3个构造函数：<br style="padding:0px; margin:0px; line-height:1.5em" />DatagramSocket()：通常用于客户端编程，它并没有特定监听的端口，仅仅使用一个临时的。程序会让操作系统分配一个可用的端口。<br style="padding:0px; margin:0px; line-height:1.5em" />DatagramSocket(int port)：创建实例，并固定监听Port端口的报文。通常用于服务端</p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px">DatagramSocket(int port, InetAddress localAddr)：这是个非常有用的构建器，当一台机器拥有多于一个IP地址的时候，由它创建的实例仅仅接收来自LocalAddr的报文。<br style="padding:0px; margin:0px; line-height:1.5em" />DatagramSocket具有的主要方法如下：<br style="padding:0px; margin:0px; line-height:1.5em" />1）receive(DatagramPacket d)：接收数据报文到d中。receive方法产生一个“阻塞”。“阻塞”是一个专业名词，它会产生一个内部循环，使程序暂停在这个地方，直到一个条件触发。</p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px">2）send(DatagramPacket dp)：发送报文dp到目的地。</p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px">3）setSoTimeout(int timeout)：设置超时时间，单位为毫秒。</p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px">4）close()：关闭DatagramSocket。在应用程序退出的时候，通常会主动释放资源，关闭Socket，但是由于异常地退出可能造成资源无法回收。所以，应该在程序完成时，主动使用此方法关闭Socket，或在捕获到异常抛出后关闭Socket。</p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px">3. DatagramPacket<br style="padding:0px; margin:0px; line-height:1.5em" />用于处理报文，它将Byte数组、目标地址、目标端口等数据包装成报文或者将报文拆卸成Byte数组。应用程序在产生数据包是应该注意，TCP/IP规定数据报文大小最多包含65507个，通常主机接收548个字节，但大多数平台能够支持8192字节大小的报文。DatagramPacket类的构建器共有4个：<br style="padding:0px; margin:0px; line-height:1.5em" />DatagramPacket(byte[] buf, int length)：将数据包中Length长的数据装进Buf数组，一般用来接收客户端发送的数据。<br style="padding:0px; margin:0px; line-height:1.5em" />DatagramPacket(byte[] buf, int offset, int length)：将数据包中从Offset开始、Length长的数据装进Buf数组。<br style="padding:0px; margin:0px; line-height:1.5em" />DatagramPacket(byte[] buf, int length, InetAddress clientAddress, int clientPort)：从Buf数组中，取出Length长的数据创建数据包对象，目标是clientAddress地址，clientPort端口,通常用来发送数据给客户端。</p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px">DatagramPacket(byte[] buf, int offset, int length, InetAddress clientAddress, int clientPort)：从Buf数组中，取出Offset开始的、Length长的数据创建数据包对象，目标是clientAddress地址，clientPort端口，通常用来发送数据给客户端。<br style="padding:0px; margin:0px; line-height:1.5em" />主要的方法如下：<br style="padding:0px; margin:0px; line-height:1.5em" />1）getData(): 从实例中取得报文的Byte数组编码。<br style="padding:0px; margin:0px; line-height:1.5em" />2）setDate(byte[] buf)：将byte数组放入要发送的报文中。<br style="padding:0px; margin:0px; line-height:1.5em" /><span style="padding:0px; margin:0px; line-height:1.5em">四. 实例解析<br style="padding:0px; margin:0px; line-height:1.5em" /></span>下面让我们来看一个UDP的服务端和客户端交互通信的例子，在本例中，服务端循环等待客户端发送的信息，并对其进行回应，客户端向服务端发送信息，并接收服务端的回应信息。代码如下：<br style="padding:0px; margin:0px; line-height:1.5em" />1.UDP的服务端程序</p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px"></p><p style="padding-top:0px; padding-bottom:0px; margin-top:0px; margin-bottom:0px; font-size:14px; font-family:verdana,arial,helvetica,sans-serif; line-height:21px"></p><div class="dp-highlighter bg_java"><div class="bar"><div class="tools"><strong>[java]</strong> <a target=_blank href="#" class="ViewSource" title="view plain">view plain</a><a target=_blank href="#" class="CopyToClipboard" title="copy">copy</a><a target=_blank href="#" class="PrintSource" title="print">print</a><a target=_blank href="#" class="About" title="?">?</a><div style="position: absolute; left: 770px; top: 1521px; width: 31px; height: 16px; z-index: 99;"><embed id="ZeroClipboardMovie_2" src="http://static.blog.youkuaiyun.com/scripts/ZeroClipboard/ZeroClipboard.swf" loop="false" menu="false" quality="best" bgcolor="#ffffff" width="31" height="16" name="ZeroClipboardMovie_2" align="middle" allowscriptaccess="always" allowfullscreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer" flashvars="id=2&width=31&height=16" wmode="transparent" /></div></div></div><ol start="1" class="dp-j"><li class="alt"><span><span class="keyword">import</span><span> java.io.IOException; </span></span></li><li><span><span class="keyword">import</span><span> java.net.DatagramPacket; </span></span></li><li class="alt"><span><span class="keyword">import</span><span> java.net.DatagramSocket; </span></span></li><li><span><span class="keyword">import</span><span> java.net.InetAddress; </span></span></li><li class="alt"><span><span class="keyword">import</span><span> java.net.InetSocketAddress; </span></span></li><li><span><span class="keyword">import</span><span> java.net.SocketException; </span></span></li><li class="alt"><span> </span></li><li><span><span class="comment">/** </span> </span></li><li class="alt"><span><span class="comment"> * Copyright 2007 GuangZhou Cotel Co. Ltd. </span> </span></li><li><span><span class="comment"> * All right reserved. </span> </span></li><li class="alt"><span><span class="comment"> * UTP服务类. </span> </span></li><li><span><span class="comment"> * @author QPING</span> </span></li><li class="alt"><span><span class="comment"> */</span><span> </span></span></li><li><span><span class="keyword">public</span><span> </span><span class="keyword">class</span><span> UdpServerSocket { </span></span></li><li class="alt"><span> <span class="keyword">private</span><span> </span><span class="keyword">byte</span><span>[] buffer = </span><span class="keyword">new</span><span> </span><span class="keyword">byte</span><span>[</span><span class="number">1024</span><span>]; </span></span></li><li><span> </span></li><li class="alt"><span> <span class="keyword">private</span><span> DatagramSocket ds = </span><span class="keyword">null</span><span>; </span></span></li><li><span> </span></li><li class="alt"><span> <span class="keyword">private</span><span> DatagramPacket packet = </span><span class="keyword">null</span><span>; </span></span></li><li><span> </span></li><li class="alt"><span> <span class="keyword">private</span><span> InetSocketAddress socketAddress = </span><span class="keyword">null</span><span>; </span></span></li><li><span> </span></li><li class="alt"><span> <span class="keyword">private</span><span> String orgIp; </span></span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 构造函数，绑定主机和端口. </span> </span></li><li class="alt"><span><span class="comment"> * @param host 主机 </span> </span></li><li><span><span class="comment"> * @param port 端口 </span> </span></li><li class="alt"><span><span class="comment"> * @throws Exception </span> </span></li><li><span><span class="comment"> */</span><span> </span></span></li><li class="alt"><span> <span class="keyword">public</span><span> UdpServerSocket(String host, </span><span class="keyword">int</span><span> port) </span><span class="keyword">throws</span><span> Exception { </span></span></li><li><span> socketAddress = <span class="keyword">new</span><span> InetSocketAddress(host, port); </span></span></li><li class="alt"><span> ds = <span class="keyword">new</span><span> DatagramSocket(socketAddress); </span></span></li><li><span> System.out.println(<span class="string">"服务端启动!"</span><span>); </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> String getOrgIp() { </span></span></li><li><span> <span class="keyword">return</span><span> orgIp; </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 设置超时时间，该方法必须在bind方法之后使用. </span> </span></li><li class="alt"><span><span class="comment"> * @param timeout 超时时间 </span> </span></li><li><span><span class="comment"> * @throws Exception </span> </span></li><li class="alt"><span><span class="comment"> */</span><span> </span></span></li><li><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> </span><span class="keyword">void</span><span> setSoTimeout(</span><span class="keyword">int</span><span> timeout) </span><span class="keyword">throws</span><span> Exception { </span></span></li><li class="alt"><span> ds.setSoTimeout(timeout); </span></li><li><span> } </span></li><li class="alt"><span> </span></li><li><span> <span class="comment">/** </span> </span></li><li class="alt"><span><span class="comment"> * 获得超时时间. </span> </span></li><li><span><span class="comment"> * @return 返回超时时间. </span> </span></li><li class="alt"><span><span class="comment"> * @throws Exception </span> </span></li><li><span><span class="comment"> */</span><span> </span></span></li><li class="alt"><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> </span><span class="keyword">int</span><span> getSoTimeout() </span><span class="keyword">throws</span><span> Exception { </span></span></li><li><span> <span class="keyword">return</span><span> ds.getSoTimeout(); </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 绑定监听地址和端口. </span> </span></li><li class="alt"><span><span class="comment"> * @param host 主机IP </span> </span></li><li><span><span class="comment"> * @param port 端口 </span> </span></li><li class="alt"><span><span class="comment"> * @throws SocketException </span> </span></li><li><span><span class="comment"> */</span><span> </span></span></li><li class="alt"><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> </span><span class="keyword">void</span><span> bind(String host, </span><span class="keyword">int</span><span> port) </span><span class="keyword">throws</span><span> SocketException { </span></span></li><li><span> socketAddress = <span class="keyword">new</span><span> InetSocketAddress(host, port); </span></span></li><li class="alt"><span> ds = <span class="keyword">new</span><span> DatagramSocket(socketAddress); </span></span></li><li><span> } </span></li><li class="alt"><span> </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 接收数据包，该方法会造成线程阻塞. </span> </span></li><li class="alt"><span><span class="comment"> * @return 返回接收的数据串信息 </span> </span></li><li><span><span class="comment"> * @throws IOException </span> </span></li><li class="alt"><span><span class="comment"> */</span><span> </span></span></li><li><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> String receive() </span><span class="keyword">throws</span><span> IOException { </span></span></li><li class="alt"><span> packet = <span class="keyword">new</span><span> DatagramPacket(buffer, buffer.length); </span></span></li><li><span> ds.receive(packet); </span></li><li class="alt"><span> orgIp = packet.getAddress().getHostAddress(); </span></li><li><span> String info = <span class="keyword">new</span><span> String(packet.getData(), </span><span class="number">0</span><span>, packet.getLength()); </span></span></li><li class="alt"><span> System.out.println(<span class="string">"接收信息："</span><span> + info); </span></span></li><li><span> <span class="keyword">return</span><span> info; </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 将响应包发送给请求端. </span> </span></li><li class="alt"><span><span class="comment"> * @param bytes 回应报文 </span> </span></li><li><span><span class="comment"> * @throws IOException </span> </span></li><li class="alt"><span><span class="comment"> */</span><span> </span></span></li><li><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> </span><span class="keyword">void</span><span> response(String info) </span><span class="keyword">throws</span><span> IOException { </span></span></li><li class="alt"><span> System.out.println(<span class="string">"客户端地址 : "</span><span> + packet.getAddress().getHostAddress() </span></span></li><li><span> + <span class="string">",端口："</span><span> + packet.getPort()); </span></span></li><li class="alt"><span> DatagramPacket dp = <span class="keyword">new</span><span> DatagramPacket(buffer, buffer.length, packet </span></span></li><li><span> .getAddress(), packet.getPort()); </span></li><li class="alt"><span> dp.setData(info.getBytes()); </span></li><li><span> ds.send(dp); </span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 设置报文的缓冲长度. </span> </span></li><li class="alt"><span><span class="comment"> * @param bufsize 缓冲长度 </span> </span></li><li><span><span class="comment"> */</span><span> </span></span></li><li class="alt"><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> </span><span class="keyword">void</span><span> setLength(</span><span class="keyword">int</span><span> bufsize) { </span></span></li><li><span> packet.setLength(bufsize); </span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 获得发送回应的IP地址. </span> </span></li><li class="alt"><span><span class="comment"> * @return 返回回应的IP地址 </span> </span></li><li><span><span class="comment"> */</span><span> </span></span></li><li class="alt"><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> InetAddress getResponseAddress() { </span></span></li><li><span> <span class="keyword">return</span><span> packet.getAddress(); </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 获得回应的主机的端口. </span> </span></li><li class="alt"><span><span class="comment"> * @return 返回回应的主机的端口. </span> </span></li><li><span><span class="comment"> */</span><span> </span></span></li><li class="alt"><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> </span><span class="keyword">int</span><span> getResponsePort() { </span></span></li><li><span> <span class="keyword">return</span><span> packet.getPort(); </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">/** </span> </span></li><li><span><span class="comment"> * 关闭udp监听口. </span> </span></li><li class="alt"><span><span class="comment"> */</span><span> </span></span></li><li><span> <span class="keyword">public</span><span> </span><span class="keyword">final</span><span> </span><span class="keyword">void</span><span> close() { </span></span></li><li class="alt"><span> <span class="keyword">try</span><span> { </span></span></li><li><span> ds.close(); </span></li><li class="alt"><span> } <span class="keyword">catch</span><span> (Exception ex) { </span></span></li><li><span> ex.printStackTrace(); </span></li><li class="alt"><span> } </span></li><li><span> } </span></li><li class="alt"><span> </span></li><li><span> <span class="comment">/** </span> </span></li><li class="alt"><span><span class="comment"> * 测试方法. </span> </span></li><li><span><span class="comment"> * @param args </span> </span></li><li class="alt"><span><span class="comment"> * @throws Exception </span> </span></li><li><span><span class="comment"> */</span><span> </span></span></li><li class="alt"><span> <span class="keyword">public</span><span> </span><span class="keyword">static</span><span> </span><span class="keyword">void</span><span> main(String[] args) </span><span class="keyword">throws</span><span> Exception { </span></span></li><li><span> String serverHost = <span class="string">"127.0.0.1"</span><span>; </span></span></li><li class="alt"><span> <span class="keyword">int</span><span> serverPort = </span><span class="number">3344</span><span>; </span></span></li><li><span> UdpServerSocket udpServerSocket = <span class="keyword">new</span><span> UdpServerSocket(serverHost, serverPort); </span></span></li><li class="alt"><span> <span class="keyword">while</span><span> (</span><span class="keyword">true</span><span>) { </span></span></li><li><span> udpServerSocket.receive(); </span></li><li class="alt"><span> udpServerSocket.response(<span class="string">"你好,sterning!"</span><span>); </span></span></li><li><span> </span></li><li class="alt"><span> } </span></li><li><span> } </span></li><li class="alt"><span>} </span></li></ol></div><pre name="code" class="java" style="display: none;">import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketException;
/**
* Copyright 2007 GuangZhou Cotel Co. Ltd.
* All right reserved.
* UTP服务类.
* @author QPING
*/
public class UdpServerSocket {
private byte[] buffer = new byte[1024];
private DatagramSocket ds = null;
private DatagramPacket packet = null;
private InetSocketAddress socketAddress = null;
private String orgIp;
/**
* 构造函数，绑定主机和端口.
* @param host 主机
* @param port 端口
* @throws Exception
*/
public UdpServerSocket(String host, int port) throws Exception {
socketAddress = new InetSocketAddress(host, port);
ds = new DatagramSocket(socketAddress);
System.out.println("服务端启动!");
}
public final String getOrgIp() {
return orgIp;
}
/**
* 设置超时时间，该方法必须在bind方法之后使用.
* @param timeout 超时时间
* @throws Exception
*/
public final void setSoTimeout(int timeout) throws Exception {
ds.setSoTimeout(timeout);
}
/**
* 获得超时时间.
* @return 返回超时时间.
* @throws Exception
*/
public final int getSoTimeout() throws Exception {
return ds.getSoTimeout();
}
/**
* 绑定监听地址和端口.
* @param host 主机IP
* @param port 端口
* @throws SocketException
*/
public final void bind(String host, int port) throws SocketException {
socketAddress = new InetSocketAddress(host, port);
ds = new DatagramSocket(socketAddress);
}
/**
* 接收数据包，该方法会造成线程阻塞.
* @return 返回接收的数据串信息
* @throws IOException
*/
public final String receive() throws IOException {
packet = new DatagramPacket(buffer, buffer.length);
ds.receive(packet);
orgIp = packet.getAddress().getHostAddress();
String info = new String(packet.getData(), 0, packet.getLength());
System.out.println("接收信息：" + info);
return info;
}
/**
* 将响应包发送给请求端.
* @param bytes 回应报文
* @throws IOException
*/
public final void response(String info) throws IOException {
System.out.println("客户端地址 : " + packet.getAddress().getHostAddress()
+ ",端口：" + packet.getPort());
DatagramPacket dp = new DatagramPacket(buffer, buffer.length, packet
.getAddress(), packet.getPort());
dp.setData(info.getBytes());
ds.send(dp);
}
/**
* 设置报文的缓冲长度.
* @param bufsize 缓冲长度
*/
public final void setLength(int bufsize) {
packet.setLength(bufsize);
}
/**
* 获得发送回应的IP地址.
* @return 返回回应的IP地址
*/
public final InetAddress getResponseAddress() {
return packet.getAddress();
}
/**
* 获得回应的主机的端口.
* @return 返回回应的主机的端口.
*/
public final int getResponsePort() {
return packet.getPort();
}
/**
* 关闭udp监听口.
*/
public final void close() {
try {
ds.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
/**
* 测试方法.
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
String serverHost = "127.0.0.1";
int serverPort = 3344;
UdpServerSocket udpServerSocket = new UdpServerSocket(serverHost, serverPort);
while (true) {
udpServerSocket.receive();
udpServerSocket.response("你好,sterning!");
}
}
} 2. UDP客户端程序
- import java.io.*;
- import java.net.*;
- /**
- * Copyright 2007 GuangZhou Cotel Co. Ltd.
- * All right reserved.
- * UDP客户端程序，用于对服务端发送数据，并接收服务端的回应信息.
- * @author QPING
- */
- public class UdpClientSocket {
- private byte[] buffer = new byte[1024];
- private DatagramSocket ds = null;
- /**
- * 构造函数，创建UDP客户端
- * @throws Exception
- */
- public UdpClientSocket() throws Exception {
- ds = new DatagramSocket();
- }
- /**
- * 设置超时时间，该方法必须在bind方法之后使用.
- * @param timeout 超时时间
- * @throws Exception
- */
- public final void setSoTimeout(final int timeout) throws Exception {
- ds.setSoTimeout(timeout);
- }
- /**
- * 获得超时时间.
- * @return 返回超时时间
- * @throws Exception
- */
- public final int getSoTimeout() throws Exception {
- return ds.getSoTimeout();
- }
- public final DatagramSocket getSocket() {
- return ds;
- }
- /**
- * 向指定的服务端发送数据信息.
- * @param host 服务器主机地址
- * @param port 服务端端口
- * @param bytes 发送的数据信息
- * @return 返回构造后俄数据报
- * @throws IOException
- */
- public final DatagramPacket send(final String host, final int port,
- final byte[] bytes) throws IOException {
- DatagramPacket dp = new DatagramPacket(bytes, bytes.length, InetAddress
- .getByName(host), port);
- ds.send(dp);
- return dp;
- }
- /**
- * 接收从指定的服务端发回的数据.
- * @param lhost 服务端主机
- * @param lport 服务端端口
- * @return 返回从指定的服务端发回的数据.
- * @throws Exception
- */
- public final String receive(final String lhost, final int lport)
- throws Exception {
- DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
- ds.receive(dp);
- String info = new String(dp.getData(), 0, dp.getLength());
- return info;
- }
- /**
- * 关闭udp连接.
- */
- public final void close() {
- try {
- ds.close();
- } catch (Exception ex) {
- ex.printStackTrace();
- }
- }
- /**
- * 测试客户端发包和接收回应信息的方法.
- * @param args
- * @throws Exception
- */
- public static void main(String[] args) throws Exception {
- UdpClientSocket client = new UdpClientSocket();
- String serverHost = "127.0.0.1";
- int serverPort = 3344;
- client.send(serverHost, serverPort, ("你好，阿蜜果!").getBytes());
- String info = client.receive(serverHost, serverPort);
- System.out.println("服务端回应数据：" + info);
- }
- }
import java.io.*;
import java.net.*;
/**
* Copyright 2007 GuangZhou Cotel Co. Ltd.
* All right reserved.
* UDP客户端程序，用于对服务端发送数据，并接收服务端的回应信息.
* @author QPING
*/
public class UdpClientSocket {
private byte[] buffer = new byte[1024];
private DatagramSocket ds = null;
/**
* 构造函数，创建UDP客户端
* @throws Exception
*/
public UdpClientSocket() throws Exception {
ds = new DatagramSocket();
}
/**
* 设置超时时间，该方法必须在bind方法之后使用.
* @param timeout 超时时间
* @throws Exception
*/
public final void setSoTimeout(final int timeout) throws Exception {
ds.setSoTimeout(timeout);
}
/**
* 获得超时时间.
* @return 返回超时时间
* @throws Exception
*/
public final int getSoTimeout() throws Exception {
return ds.getSoTimeout();
}
public final DatagramSocket getSocket() {
return ds;
}
/**
* 向指定的服务端发送数据信息.
* @param host 服务器主机地址
* @param port 服务端端口
* @param bytes 发送的数据信息
* @return 返回构造后俄数据报
* @throws IOException
*/
public final DatagramPacket send(final String host, final int port,
final byte[] bytes) throws IOException {
DatagramPacket dp = new DatagramPacket(bytes, bytes.length, InetAddress
.getByName(host), port);
ds.send(dp);
return dp;
}
/**
* 接收从指定的服务端发回的数据.
* @param lhost 服务端主机
* @param lport 服务端端口
* @return 返回从指定的服务端发回的数据.
* @throws Exception
*/
public final String receive(final String lhost, final int lport)
throws Exception {
DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
ds.receive(dp);
String info = new String(dp.getData(), 0, dp.getLength());
return info;
}
/**
* 关闭udp连接.
*/
public final void close() {
try {
ds.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
/**
* 测试客户端发包和接收回应信息的方法.
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
UdpClientSocket client = new UdpClientSocket();
String serverHost = "127.0.0.1";
int serverPort = 3344;
client.send(serverHost, serverPort, ("你好，阿蜜果!").getBytes());
String info = client.receive(serverHost, serverPort);
System.out.println("服务端回应数据：" + info);
}
} 原文连接：http://sishuok.com/forum/blogPost/list/466.html
扫一扫
268
被折叠的 条评论
为什么被折叠?
到【灌水乐园】发言
