套接字编程实验报告.docx

Programing 实验物联2班 201208080228 赵智慧一、 实验题目：利用套接字编程，编写出TCP和UDP的客户机、服务器程序进行交互二、 实验代码：1. TCP服务器：package TCP;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import .ServerSocket;import .Socket;public class TCPServer public static void main(String args) throws IOExceptionServerSocket server=new ServerSocket(7999);System.out.println(server ok);Socket socket=server.accept();BufferedReader bf=new BufferedReader(new InputStreamReader(socket.getInputStream();String str=bf.readLine();while(str!=null)System.out.println(str);str=bf.readLine();2. TCP客户机：package TCP;import java.io.BufferedReader;import java.io.DataOutputStream;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.PrintWriter;import .Socket;import .UnknownHostException;public class TCPClient public static void main(String args) throws UnknownHostException, IOExceptionString sentence;InputStreamReader isr = new InputStreamReader(System.in);BufferedReader inFromUser = new BufferedReader(isr);Socket clientSocket = new Socket(,7999);sentence = inFromUser.readLine(); OutputStream os = clientSocket.getOutputStream();PrintWriter oos=new PrintWriter(os);os.write(sentence.getBytes();clientSocket.close();3. UDP服务器：package UDP;import .DatagramPacket;import .DatagramSocket;import .InetAddress;import .SocketException;public class UDPServer public static void main(String args) throws ExceptionDatagramSocket serverSocket = new DatagramSocket(9876); /所有发送和接收的数据都将通过该套接字 /因为UDP无连接，所以无需创建一个新的套接字监听新的请求byte receive1 = new byte1024;byte receive2 = new byte1024;byte send1 = new byte1024;byte send2 = new byte1024;byte send3 = new byte1024;while(true)DatagramPacket receivePacket = new DatagramPacket(receive1, receive1.length);serverSocket.receive(receivePacket);String str = new String(receivePacket.getData(); /从分组中提取出数据，并存入str中InetAddress ip = receivePacket.getAddress(); /提取IP地址int port = receivePacket.getPort(); /提取客户机端口号String ask = 请选择:1.将其转化为大写 2.将a字符替换为c字符;send1 = ask.getBytes();DatagramPacket sendPacket1 = new DatagramPacket(send1, send1.length, ip,port);serverSocket.send(sendPacket1);DatagramPacket receivePacket2 = new DatagramPacket(receive2, receive2.length);serverSocket.receive(receivePacket2);String str2 = new String(receivePacket2.getData();if(str2.toCharArray()0=1)String capitalizedSentence = str.toUpperCase();send3 = capitalizedSentence.getBytes();DatagramPacket sendPacket3 = new DatagramPacket(send3, send3.length, ip,port);serverSocket.send(sendPacket3);else String change = str.replace(a, c); send2 = change.getBytes(); DatagramPacket sendPacket2 = new DatagramPacket(send2, send2.length, ip,port); serverSocket.send(sendPacket2);4. 客户机：package UDP;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import .DatagramPacket;import .DatagramSocket;import .InetAddress;import .SocketException;import .UnknownHostException;public class UDPClient public static void main(String args) throws IOExceptionInputStreamReader isr = new InputStreamReader(System.in);BufferedReader inFromUser = new BufferedReader(isr);DatagramSocket clientSocket = new DatagramSocket(); /客户机套接字InetAddress IPAddress = InetAddress.getByName(); byte sendData1 = new byte1024;byte sendData2 = new byte1024;byte receiveData1 = new byte1024;byte receiveData2 = new byte1024;String sentence = inFromUser.readLine();sendData1 = sentence.getBytes();DatagramPacket sendPacket = new DatagramPacket(sendData1, sendData1.length,IPAddress,9876);clientSocket.send(sendPacket);DatagramPacket receivePacket1 = new DatagramPacket(receiveData1, receiveData1.length);clientSocket.receive(receivePacket1);String modifiedData1 = new String(receivePacket1.getData();System.out.println(Server:+modifiedData1);String sentence2 = inFromUser.readLine();sendData2 = sentence2.getBytes();DatagramPacket sendPacket2 = new DatagramPacket(sendData2, sendData2.length,IPAddress,9876);clientSocket.send(sendPacket2);DatagramPacket receivePacket2 = new DatagramPacket(receiveData2, receiveData2.length);clientSocket.receive(receivePacket2);String modifiedData2 = new String(receivePacket2.getData();System.out.println(Server:+modifiedData2);clientSocket.close();三、 实验分析：TCP提供可靠的数据传输，而UDP提供不可靠的运输服务，在套接字编程方面，UDP客户机使用的是DatagramSocket，而TCP客户机使用的是Socket。TCP实现：（1） 客户机从键盘输入读取一行字符，并通过套接字将该行发送到服务器（2） 服务器从其套接字读取一行数据（3） 服务器将来自客户机的数据打印出来UDP实现：（1） 客户机从其键盘输入读取一行字符，并通过套接字将该行发送到服务器（2） 服务器从其套接字读取一行数据（3） 服务器发送可供选择的操作信息发送给客户机（4） 客户机从其套接字读取来自服务器的信息，并将其选择通过套接字发送给服务器（5） 服务器通过套接字读取到客户机的选择，并根据是选择转换大小写还是选择替换字符来将修改后的行通过套接字发送给客户机（6） 客户机从其套接字中读取按照自己选择修改后的行，并打印显示出来四、 运行结果：TCP套接字：运行TCPServer 之后：再运行TCPClient：则TCPServer会显示：UDP套接字：五、问题思考：1. 在一台主机上安装编译用Java写的TCPClient和UDPClient程序，在另一台主机上安装编译TCPServer和UDPServer程序a. 如果你在运行TCPServer之前运行TCPClient，将发生什么现象，为什么？会报错，因为TCP是面向连接的传输，所以未开启服务器时先开启客户机不能通过三次握手建立连接，也就无法传输数据。b. 如果你在运行UDPServer之前运行UDPClient，将发生什么现象，为什么？没什么变化，因为UDP是无连接的，先开启服务器还是客户机都没有影响。c. 如果对客户端和服务器使用了不同的端口，将发生什么现象？不影响数据传输。2假定在UDPClient.java中，我们使用 DatagramSocket clientSocket = new DatagramSocket( 5432 ); 代替 DatagramSocket clientSocket = new DatagramSocket(); 在U