使用 UDP协议的 Socket 网络程序设计 java编程.doc

实验四 使用 UDP协议的 Socket 网络程序设计 及实验步骤详解！实验目的：掌握 Socket 通讯机制，掌握 DataGramSocket 和 DataGramPacket类和相关方法。 实验要求：通过Socket 编程，掌握网络应用程序的开发方法；掌握利用Java提供的基本组件进行网络传输；掌握 Java 提供的多线程机制，异常处理机制和低层对协议的通信机制，通过 Socket 编程，掌握网络应用程序的开发方法。1、import .*;public class DatagramPacketExa public static void main(String args) throws SocketException String s = This is a test.; byte data = s.getBytes(); try InetAddress ia = InetAddress.getByName(); int port = 7; SocketAddress sa=new InetSocketAddress(ia,port); DatagramPacket dp = new DatagramPacket(data, data.length, ia, port); DatagramPacket dp1= new DatagramPacket(data, data.length, sa); System.out.println(This packet is addressed to: + dp.getAddress(); 分别调用数据报dp的方法，dp.getData(), dp.getOffset(), dp.getLength(),getLength().结果是什么？ catch (UnknownHostException e) System.err.println(e); 调试并输出结果。2、编写一个能扫描出本地机所有udp端口的程序。3、建立三个类，然后运行服务器端和客户端。当客户端启动后，服务器端得到客户端的地址和端口信息，同时客户端会收到客户端发送的reply信息。 类DataGramHelper import .*;public class DataGramHelper /定义一个数据包public StringtoDatagram(String s, InetAddress ip, int port) / 将String容纳到Byte数组里byte buf = bytes.length() + 1;/ 调整编码buf = s.getBytes();/ 返回构造对象 选择一条语句插到横线空白处，注意要改造一下DatagramPacket(byte buf, int length) 构建数据报包，接收length长度的包并放入buf。 DatagramPacket(byte buf, int length, InetAddress address, int port) 构建数据报包，发送length长度的包到address指定的主机的port端口。return new public String DatagramtoString(DatagramPacket p) return new String(p.getData(), 0, p.getLength();客户端代码import java.io.*;import java.lang.*;import .*;public class UDPClient public static void main(String args) / UDP SocketDatagramSocket udpCliSocket;DatagramPacket udpSendPacket;DatagramPacket udpReceivePacket;/ 定义报文的工具类DataGramHelper datapacketHelper = new DataGramHelper();/ 报文字节数组byte packetArray;/ 通讯内容String content = hello Server;try / 指定端口号3335，避免与其他应用程序发生冲突 选择一条语句插到横线空白处，注意要改造一下public DatagramSocket() 构建数据报Socket，绑定到本地主机上的任意端口。 public DatagramSocket(int port) 构建一个数据报Socket，将它绑定到指定的port端口。public DatagramSocket(int port, InetAddress laddr) 构建一个数据报Socket，绑定到指定的laddr本地地址和port端口udpCliSocket = new packetArray = new byte1024;/ 将字符串转换为字节数组packetArray = content.getBytes();解释该语句udpSendPacket = new DatagramPacket(packetArray, packetArray.length,InetAddress.getByName(localhost), 3334);/ 发送消息udpCliSocket. (udpSendPacket);/ 接收消息udpReceivePacket = new DatagramPacket(packetArray,packetArray.length);udpCliSocket. (udpReceivePacket);/ 输出结果System.out.println(datapacketHelper.DatagramtoString(udpReceivePacket);填写异常类型 catch ( e) System.err.println(Client UDP Socket error!);System.exit(1); catch (IOException e) System.err.println(IO error);e.printStackTrace(); catch (Exception e) e.printStackTrace();服务器端代码import .*;import java.io.*;public class UDPServer public static void main(String args) /定义控制UDP通讯的DatagramSocketDatagramSocket socket;/转换DataGrammer的帮助类DataGramHelper datapacketHelper;byte buf = new byte1024; 选择一条语句插到横线空白处，注意要改造一下DatagramPacket(byte buf, int length) 构建数据报包，接收length长度的包并放入buf。 DatagramPacket(byte buf, int length, InetAddress address, int port) 构建数据报包，发送length长度的包到address指定的主机的port端口。DatagramPacket datagrampacket = new ;try socket = new DatagramSocket(3334);注释上面一句 / System.out.println(Start UDP Server!);datapacketHelper = new DataGramHelper();/ 在此阻塞socket.receive(datagrampacket);String rcvd = datapacketHelper.DatagramtoString(datagrampacket)+ , from address: + datagrampacket.getAddress()+ , port: + datagrampacket.getPort();System.out.println(rcvd);/收到后回送String replyStr = reply;DatagramPacket replyDatagram = datapacketHelper.StringtoDatagram(replyStr,datagrampacket.getAddress(), datagrampacket.getPort();socket.send(replyDatagram); catch (SocketException e) System.err.println(Server UDP Socket error!);System.exit(1); catch (IOException e) System.err.println(IO error);e.printStackTrace(); catch (Exception e) e.printStackTrace();编译并运行程序实验心得实验步骤：1、建立DataGramHelper java类package newpackage;/* * * author labuser */import .*;public class DataGramHelper public DatagramPacket StringtoDatagram(String s, InetAddress ip, int port) / 将String容纳到Byte数组里 byte buf = new bytes.length() + 1; / 调整编码 buf = s.getBytes(); / 返回构造对象 return new DatagramPacket(buf, buf.length, ip, port); public String DatagramtoString(DatagramPacket p) return new String(p.getData(), 0, p.getLength(); 2、建立DatagramPacketExa java类package newpackage;/* * * author labuser */import .*;public class DatagramPacketExa public DatagramPacket StringtoDatagram(String s, InetAddress ip, int port) / 将String容纳到Byte数组里 byte buf = new bytes.length() + 1; / 调整编码 buf = s.getBytes(); / 返回构造对象 return new DatagramPacket(buf, buf.length, ip, port); public String DatagramtoString(DatagramPacket p) return new String(p.getData(), 0, p.getLength(); 3、建立Test java类package newpackage;/* * * author labuser */import .*; public class Test public static void main(String args) for (int port=1024;port=65535;port+) try DatagramSocket server=new DatagramSocket(port); server.close(); catch(SocketException e) System.out.println(there is a server in port +port+.); 4、建立UDPClient java类package newpackage;/* * * author labuser */import java.io.*;import java.lang.*;import .*;public class UDPClient public static void main(String args) / UDP Socket DatagramSocket udpCliSocket; DatagramPacket udpSendPacket; DatagramPacket udpReceivePacket; / 定义报文的工具类 DataGramHelper datapacketHelper = new DataGramHelper(); / 报文字节数组 byte packetArray; / 通讯内容 String content = hello Server; try / 指定端口号，避免与其他应用程序发生冲突 udpCliSocket = new DatagramSocket(3335); packetArray = new byte1024; / 将字符串转换为字节数组 packetArray = content.getBytes(); udpSendPacket = new DatagramPacket(packetArray, packetArray.length, InetAddress.getByName(localhost), 3334); / 发送消息 udpCliSocket.send(udpSendPacket); / 接收消息 udpReceivePacket = new DatagramPacket(packetArray, packetArray.length); udpCliSocket.receive(udpReceivePacket); / 输出结果 System.out.println(datapacketHelper.DatagramtoString(udpReceivePacket); catch (SocketException e) System.err.println(Client UDP Socket error!); System.exit(1); catch (IOException e) System.err.println(IO error); e.printStackTrace(); catch (Exception e) e.printStackTrace(); 5、建立UDPServer java类package newpackage;/* * * author labuser */import .*;import java.io.*;public class UDPServer public static void main(String args) /定义控制UDP通讯的DatagramSocket DatagramSocket socket; /转换DataGrammer的帮助类 DataGramHelper datapacketHelper; byte buf = new byte1024; DatagramPacket datagrampacket = new DatagramPacket(buf, buf.length); try / 根据端口号，实例化DatagramSocke