java网络编程应该怎样在客户端和服务器间实现通信？

Question

如题所述

Answer 1

以前写的，照贴了。。。服务器端：import java.awt.*;\x0d\x0aimport java.awt.event.WindowAdapter;\x0d\x0aimport java.awt.event.WindowEvent;\x0d\x0aimport java.io.*;\x0d\x0aimport java.net.*;/*6、 采用UDP协议，编写一个Java网络应用程序，该应用分服务器端程序和客户端程序两部分。\x0d\x0a* 客户端指定一个服务器上的文件名，让服务器发回该文件的内容，或者提示文件不存在。\x0d\x0a* （20分）（服务端程序和客户端程序分别命名为Server.java和Client.java）*/\x0d\x0apublic class N4BT6 extends Frame\x0d\x0a{\x0d\x0aDatagramSocket socket ;\x0d\x0aDatagramPacket packet ;byte[] buf ;\x0d\x0aFile file ;\x0d\x0aFileInputStream input;\x0d\x0aString message = "该文件不存在";\x0d\x0aTextArea text;\x0d\x0apublic N4BT6(String title)\x0d\x0a{\x0d\x0asuper(title);\x0d\x0atext = new TextArea(6,4);\x0d\x0aadd(text);\x0d\x0asetSize(400, 300);\x0d\x0asetVisible(true);\x0d\x0aaddWindowListener(new WindowAdapter()\x0d\x0a{\x0d\x0apublic void windowClosing(WindowEvent e)\x0d\x0a{\x0d\x0adispose();\x0d\x0a}\x0d\x0a});\x0d\x0a\x0d\x0abuf = new byte[1024];\x0d\x0atry\x0d\x0a{\x0d\x0asocket = new DatagramSocket(1230);\x0d\x0apacket = new DatagramPacket(buf, buf.length);\x0d\x0asocket.receive(packet);\x0d\x0afile = new File(new String(packet.getData()));\x0d\x0asocket = new DatagramSocket();\x0d\x0a} \x0d\x0acatch (Exception e)\x0d\x0a{e.printStackTrace();\x0d\x0a}\x0d\x0a\x0d\x0aif(file.exists())\x0d\x0a{\x0d\x0atry\x0d\x0a{\x0d\x0abuf = new byte[(int)file.length()];\x0d\x0apacket = new DatagramPacket(buf,buf.length,InetAddress.getLocalHost(),1234);\x0d\x0ainput = new FileInputStream(file);\x0d\x0ainput.read(buf);\x0d\x0asocket.send(packet);\x0d\x0a}\x0d\x0acatch (IOException e) \x0d\x0a{\x0d\x0ae.printStackTrace();\x0d\x0a}\x0d\x0a}\x0d\x0aelse\x0d\x0a{\x0d\x0atry\x0d\x0a{\x0d\x0apacket = new DatagramPacket(message.getBytes(),message.getBytes().length,\x0d\x0aInetAddress.getLocalHost(),1234);\x0d\x0asocket.send(packet);\x0d\x0a}\x0d\x0acatch (Exception e) \x0d\x0a{\x0d\x0ae.printStackTrace();\x0d\x0a}\x0d\x0a}\x0d\x0a\x0d\x0a}\x0d\x0apublic static void main(String[] args)\x0d\x0a{\x0d\x0anew N4BT6("Server");\x0d\x0a}\x0d\x0a}\x0d\x0a客户端：import java.awt.*;\x0d\x0aimport java.awt.event.*;\x0d\x0aimport java.net.DatagramPacket;\x0d\x0aimport java.net.DatagramSocket;\x0d\x0aimport java.net.InetAddress;public class N4BT6_2 extends Frame\x0d\x0a{\x0d\x0aTextArea text;\x0d\x0aString message = "Q.txt";\x0d\x0aDatagramSocket socket ;\x0d\x0aDatagramPacket packet;\x0d\x0abyte[] buf;\x0d\x0apublic N4BT6_2(String title)\x0d\x0a{\x0d\x0asuper(title);\x0d\x0atext = new TextArea(6,4);\x0d\x0aadd(text);\x0d\x0asetSize(400, 300);\x0d\x0asetVisible(true);\x0d\x0aaddWindowListener(new WindowAdapter()\x0d\x0a{\x0d\x0apublic void windowClosing(WindowEvent e)\x0d\x0a{\x0d\x0adispose();\x0d\x0a}\x0d\x0a});\x0d\x0atry\x0d\x0a{\x0d\x0a\x0d\x0asocket = new DatagramSocket();\x0d\x0apacket = new DatagramPacket(message.getBytes(),message.getBytes().length,\x0d\x0aInetAddress.getLocalHost(),1230);\x0d\x0asocket.send(packet);\x0d\x0a}\x0d\x0acatch (Exception e) \x0d\x0a{\x0d\x0ae.printStackTrace();\x0d\x0a}\x0d\x0a\x0d\x0atry\x0d\x0a{\x0d\x0abuf = new byte[1024];\x0d\x0asocket = new DatagramSocket(1234);\x0d\x0apacket = new DatagramPacket(buf,buf.length);\x0d\x0asocket.receive(packet);\x0d\x0atext.append(new String(buf));\x0d\x0a}\x0d\x0acatch (Exception e) \x0d\x0a{\x0d\x0ae.printStackTrace();\x0d\x0a}\x0d\x0a}\x0d\x0apublic static void main(String[] args)\x0d\x0a{\x0d\x0anew N4BT6_2("Client");\x0d\x0a}\x0d\x0a}