java网络编程应该怎样在客户端和服务器间实现通信？

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}

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用java代码实现客户端与服务端建立连接？

套接字 Socket

import java.net.*;

Server:

ServerSocket server=new ServerSocket(port);//port是端口

Socket socket=server.accept();

//等待客户机的连接请求，若连接，则创建一套接字，并将返回。

Client:

Socket socket=new Socket("host",port);//host主机名（本机：127.0.0.1）

java,一台机器同时是客户端和服务器，服务器接收客户端信息并显示

假设你有a、b两台计算机，那么a可以向b发送文件，b也可以向a发送文件。所以在实现的时候，你的软件既要实现服务器的功能，也要实现客户端的功能。即：你的软件既可以申请发送文件，也可以在别人向你发送文件时接收文件。实现也不难，只是你判断用户需要的功能，然后根据功能实现相应的操作就行了。

java socket，我有客户端和服务器的代码，帮我添加广播和能多人会话，加分！！代码如下

根据你的改了个！不好意思，其中读写的思路稍微有点不同！不过可以做参考！

Server端代码：

import java.net.*;

import java.io.*;

import java.util.*;

public class TestServer {

ServerSocket s = null;

boolean started = false;//用来监听服务器是否启动！

ListServerReaderWriter clients = new ArrayListServerReaderWriter();//用来存放启动的客服端

public static void main(String[] args) {

new TestServer().start();

}

public void start() {

try {

s = new ServerSocket(5050);

started = true;

} catch(SocketException e) {

System.out.println("5050端口正在使用中！！！请关掉相关程序并重新运行服务器！");

System.exit(0);

} catch (IOException e) {

e.printStackTrace();

}

int i = 1;

try {

while(started) {

Socket ss = s.accept();

ServerReaderWriter c = new ServerReaderWriter(ss);//建立客服端

System.out.println("第" + i + "个客服端启动！");

++i;

new Thread(c).start();//启动线程

clients.add(c);

}

} catch (EOFException e) {

System.out.println("客服端被关闭！");

} catch (IOException e) {

e.printStackTrace();

} finally {

try {

s.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

class ServerReaderWriter implements Runnable { //建议使用Runnable避免你重写run方法麻烦！

private Socket s;

private DataInputStream dis = null;//注意赋值，养成好习惯！

private DataOutputStream dos = null;

private boolean bConnected = false;//用于调用连接成功后的run方法

public ServerReaderWriter(Socket s) {

this.s = s;

try {

dis = new DataInputStream(s.getInputStream());

dos = new DataOutputStream(s.getOutputStream());

bConnected = true;

} catch (IOException e) {

e.printStackTrace();

}

}

public void send(String str) {

try {

dos.writeUTF(str);

} catch (IOException e) {

clients.remove(this);

System.out.println("有客户退出！");

}

}

public void run() {

try {

while (bConnected) {

String input = dis.readUTF();

System.out.println(input);

for(int i=0; iclients.size(); ++i) {

ServerReaderWriter c = clients.get(i);

c.send(input);

}

}

} catch(SocketException e) {

System.out.println("一个客服端已关闭,请勿再像他发送信息！");

} catch (EOFException e) {

System.out.println("谢谢使用！");

}catch (IOException e) {

e.printStackTrace();

} finally {

try {

if (dis != null) {

dis.close();

}

if (dos != null) {

dos.close();

}

if (s != null) {

s.close();

s = null;

}

//clients.clear();

} catch (IOException e1) {

e1.printStackTrace();

}

}

}

}

}

Client端代码：

import java.io.*;

import java.net.*;

import java.awt.*;

import java.awt.event.*;

public class TestClient extends Frame { //用到Frame生产界面比较直观

Socket s = null;

DataOutputStream dos = null;

DataInputStream dis = null;

private boolean bConnected = false;

TextField tfText = new TextField();

TextArea taContent = new TextArea();

Thread tRecv = new Thread(new ClientReaderWriter());

public static void main(String[] args){

new TestClient().launchFrame();

}

public void launchFrame() {

this.setSize(300, 300); //设置客服端窗口格式

this.setLocation(400, 300);

add(tfText, BorderLayout.SOUTH);

add(taContent, BorderLayout.NORTH);

this.pack();

this.addWindowListener(new WindowAdapter() { //监听窗口关闭事件

public void windowClosing(WindowEvent arg0) {

disconnect();

System.exit(0);

}

});

tfText.addActionListener(new TFListener());

setVisible(true);

connect();

tRecv.start();

}

public void connect() {

try {

s = new Socket("127.0.0.1", 5050); //依据自己的服务器，我这里用的localhost

dos = new DataOutputStream(s.getOutputStream());

dis = new DataInputStream(s.getInputStream());

System.out.println("连接服务器！");

bConnected = true;

} catch(ConnectException e) {

System.out.println("请检查服务器是否启动！");

try {

Thread.sleep(1000);

} catch (InterruptedException e1) {

e1.printStackTrace();

}

System.exit(0);

}

catch (UnknownHostException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

public void disconnect() {

try {

dos.close();

dis.close();

s.close();

} catch (IOException e) {

e.printStackTrace();

}

}

private class TFListener implements ActionListener {

public void actionPerformed(ActionEvent e) {

String str = tfText.getText().trim();

tfText.setText("");

try {

dos.writeUTF(str);

if(str.equals("bye")){

System.exit(0);

}

dos.flush();

} catch (IOException e1) {

e1.printStackTrace();

}

}

}

class ClientReaderWriter implements Runnable {

public void run() {

try {

while(bConnected) {

String input = dis.readUTF();

taContent.setText(taContent.getText() + input +'\n');

}

} catch (SocketException e) {

System.out.println("轻轻的我走了！Bye-bye!");

} catch (EOFException e) {

System.out.println("我断网了，再见!");

}

catch (IOException e) {

e.printStackTrace();

}

}

}

}

急求一段JAVA代码，有关客户端和服务器的。。。

客户端

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.io.*;

import java.net.*;

import java.util.logging.Level;

import java.util.logging.Logger;

import javax.swing.*;

/**

*

* @author Administrator

*/

public class Main extends JFrame{

JPanel jp;

JButton jb;

javax.swing.JTextField jt1;

JTextField jt2;

JTextField jt3;

JLabel jl1;

JLabel jl2;

public Main()

{

this.setBounds(150, 50, 300, 100);

jp= new JPanel(new GridLayout(3, 2));

jb=new JButton("登陆");

jt1=new JTextField();

jt2=new JTextField();

jt3=new JTextField();

jt3.setEditable(false);

jl1=new JLabel("用户名");

jl2=new JLabel("密码");

this.getContentPane().add(jp);

jp.add(jl1);

jp.add(jt1);

jp.add(jl2);

jp.add(jt2);

jp.add(jt3);

jp.add(jb);

this.setVisible(true);

jb.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

String sentence;

String modifiedSentence = null;

//BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));

Socket clientSocket = null;

try {

clientSocket = new Socket("127.0.0.1", 6789);

} catch (UnknownHostException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

//System.out.println("connection ok");

DataOutputStream outToServer = null;

try {

outToServer = new DataOutputStream(clientSocket.getOutputStream());

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

BufferedReader inFromServer = null;

try {

inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

sentence=jt1.getText()+" "+jt2.getText();

try {

//System.out.println(sentence);

outToServer.writeBytes(sentence + '\n');

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

try {

modifiedSentence = inFromServer.readLine();

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

//System.out.println("FROM SERVER:"+modifiedSentence);

jt3.setText(modifiedSentence);

try {

clientSocket.close();

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

}

});

}

/**

* @param args the command line arguments

*/

public static void main(String[] args) throws Exception

{

Main m=new Main();

}

}

服务器端

import java.io.*;

import java.net.*;

public class Main {

public static void main(String[] args) throws Exception {

String clientSentence;

String capitalizedSentence;

ServerSocket welcomeSocket=new ServerSocket(6789);

while(true){

Socket connectionSocket=welcomeSocket.accept();

BufferedReader inFromClient=new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));

DataOutputStream outToClient=new DataOutputStream(connectionSocket.getOutputStream());

clientSentence=inFromClient.readLine();

//capitalizedSentence=clientSentence.toUpperCase()+'\r'+'\n';

//outToClient.writeBytes(capitalizedSentence);

if(clientSentence.equalsIgnoreCase("admin 1234"))

outToClient.writeBytes("ok"+'\n');

else

outToClient.writeBytes("error"+'\n');

}

}

}

JAVA聊天室 客户端 和 服务器 完整代码

CS模式的QQ这是服务器:ChatServer.javaimport java.net.*;

import java.io.*;

public class ChatServer

{

final static int thePort=8189;

ServerSocket theServer;

ChatHandler[] chatters;

int numbers=0;

public static void main(String args[])

{

ChatServer app=new ChatServer();

app.run();

}

public ChatServer()

{

try

{

theServer=new ServerSocket(thePort);

chatters=new ChatHandler[10];

}

catch(IOException io){}

}

public void run()

{

try

{

System.out.println("服务器已经建立！");

while(numbers10)

{

Socket theSocket=theServer.accept();

ChatHandler chatHandler=new ChatHandler(theSocket,this);

chatters[numbers]=chatHandler;

numbers++;

}

}catch(IOException io){}

}

public synchronized void removeConnectionList(ChatHandler c)

{

int index=0;

for(int i=0;i=numbers-1;i++)

if(chatters[i]==c)index=i;

for(int i=index;inumbers-1;i++)

chatters[i]=chatters[i+1];

chatters[numbers-1]=null;

numbers--;

}

public synchronized String returnUsernameList()

{

String line="";

for(int i=0;i=numbers-1;i++)

line=line+chatters[i].user+":";

return line;

}

public void broadcastMessage(String line)

{

System.out.println("发布信息:"+line);

for(int i=0;i=numbers-1;i++)

chatters[i].sendMessage(line);

}

}====================================================这是客户端：ChatClient.javaimport java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.net.*;

import java.io.*;

public class ChatClient extends Thread implements ActionListener

{

JTextField messageField,IDField,ipField,portField;

JTextArea message,users;

JButton connect,disconnect;

String user="";

String userList[]=new String[10];

Socket theSocket;

BufferedReader in;

PrintWriter out;

boolean connected=false;

Thread thread;

public static void main(String args[])

{

JFrame frame=new JFrame("聊天室");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

ChatClient cc=new ChatClient();

JPanel content=cc.createComponents();

frame.getContentPane().add(content);

frame.setSize(550,310);

frame.setVisible(true);

}

public JPanel createComponents()

{

JPanel pane=new JPanel(new BorderLayout());

message=new JTextArea(10,35);

message.setEditable(false);

JPanel paneMsg=new JPanel();

paneMsg.setBorder(BorderFactory.createTitledBorder("聊天内容"));

paneMsg.add(message);

users=new JTextArea(10,10);

JPanel listPanel=new JPanel();

listPanel.setBorder(BorderFactory.createTitledBorder("在线用户:"));

listPanel.add(users);

messageField=new JTextField(50);

IDField=new JTextField(5);

ipField=new JTextField("LocalHost");

portField=new JTextField("8189");

connect=new JButton("连 接");

disconnect=new JButton("断 开");

disconnect.setEnabled(false);

JPanel buttonPanel=new JPanel();

buttonPanel.add(new Label("服务器IP:"));

buttonPanel.add(ipField);

buttonPanel.add(new Label("端口："));buttonPanel.add(portField);

buttonPanel.add(new Label("用户名："));

buttonPanel.add(IDField);

buttonPanel.add(connect);

buttonPanel.add(disconnect);

pane.add(messageField,"South");

pane.add(buttonPanel,"North");

pane.add(paneMsg,"Center");

pane.add(listPanel,"West");

connect.addActionListener(this);

disconnect.addActionListener(this);

messageField.addActionListener(this);

IDField.addActionListener(this);

ipField.addActionListener(this);

return pane;

}

public void actionPerformed(ActionEvent e)

{

if(e.getSource()==connect){

user=IDField.getText();

String ip=ipField.getText();

int port =Integer.parseInt(portField.getText());

if(!user.equals("")connectToServer(ip,port,user))

{

disconnect.setEnabled(true);

connect.setEnabled(false);

}

}

if(e.getSource()==disconnect)disconnectFromServer();

if(e.getSource()==messageField)

if(theSocket!=null)

{

out.println("MESSAGE:"+messageField.getText());

messageField.setText("");

}

}

public void disconnectFromServer()

{

if(theSocket!=null)

{

try

{

connected=false;

out.println("LEAVE:"+user);

disconnect.setEnabled(false);

connect.setEnabled(true);

thread=null;

theSocket.close();

}catch(IOException io){}

theSocket=null;

message.setText("");

users.setText("");

}

}

public boolean connectToServer(String ip,int port,String ID)

{

if(theSocket!=null)

return false;

try

{

theSocket=new Socket(ip,port);

in=new BufferedReader(new InputStreamReader(theSocket.getInputStream()));

out=new PrintWriter(new OutputStreamWriter(theSocket.getOutputStream()),true);

out.println("USER:"+user);

message.setText("");

connected=true;

thread=new Thread(this);

thread.start();

}catch(Exception e){return false;}

return true;

}

public void extractMessage(String line)

{

System.out.println(line);

Message messageline;

messageline=new Message(line);

if(messageline.isValid())

{

if(messageline.getType().equals("JOIN"))

{

user=messageline.getBody();

message.append(user+"进入了聊天室\n");

}

else if(messageline.getType().equals("LIST"))

updateList(messageline.getBody());

else if(messageline.getType().equals("MESSAGE"))

message.append(messageline.getBody()+"\n");

else if(messageline.getType().equals("REMOVE"))

message.append(messageline.getBody()+"离开了聊天室\n");

}

else

message.append("出现问题："+line+"\n");

}

public void updateList(String line)

{

users.setText("");

String str=line;

for(int i=0;i10;i++)

userList[i]="";

int index=str.indexOf(":");

int a=0;

while(index!=-1){

userList[a]=str.substring(0,index);

str=str.substring(index+1);

a++;

index=str.indexOf(":");

}

for(int i=0;i10;i++)

users.append(userList[i]+"\n");

}

public void run(){

try{

String line="";

while(connected line!=null){

line=in.readLine();

if(line!=null) extractMessage(line);

}

}catch(IOException e){}

}

} =======================================================import java.net.*;

import java.io.*;

class ChatHandler extends Thread{

Socket theSocket;

BufferedReader in;

PrintWriter out;

int thePort;

ChatServer parent;

String user="";

boolean disconnect=false;

public ChatHandler(Socket socket,ChatServer parent){

try{

theSocket=socket;

this.parent=parent;

in=new BufferedReader(new InputStreamReader(theSocket.getInputStream()));

out=new PrintWriter(new OutputStreamWriter(theSocket.getOutputStream()),true);

thePort=theSocket.getPort();

start();

}catch(IOException io){}

}

public void sendMessage(String line){

out.println(line);

}

public void setupUserName(String setname){

user=setname;

//System.out.print(user+"参加");

parent.broadcastMessage("JOIN:"+user);

}

public void extractMessage(String line){

Message messageline;

messageline = new Message(line);

if(messageline.isValid()){

if(messageline.getType().equals("USER")){

setupUserName(messageline.getBody());

parent.broadcastMessage("LIST:"+parent.returnUsernameList());

}

else if(messageline.getType().equals("MESSAGE")){

parent.broadcastMessage("MESSAGE:"+user+"说: "+messageline.getBody());

}

else if(messageline.getType().equals("LEAVE")){

String c=disconnectClient();

parent.broadcastMessage("REMOVE:"+c);

parent.broadcastMessage("LIST:"+parent.returnUsernameList());

}

}

else

sendMessage("命令不存在!");

}

public String disconnectClient(){

try{

in.close();

out.close();

theSocket.close();

parent.removeConnectionList(this);

disconnect=true;

}catch(Exception ex){}

return user;

}

public void run(){

String line,name;

boolean valid=false;

try{

while((line=in.readLine())!=null){

System.out.println("收到:"+line);

extractMessage(line);

}

}catch(IOException io){}

}

}

=========================================================

Message.javapublic class Message{

private String type;

private String body;

private boolean valid;

public Message(String messageLine){

valid=false;

type=body=null;

int pos=messageLine.indexOf(":");

if(pos=0){

type=messageLine.substring(0,pos).toUpperCase();

body=messageLine.substring(pos+1);

valid=true;

}

}

public Message(String type,String body){

valid=true;

this.type=type;

this.body=body;

}

public String getType(){

return type;

}

public String getBody(){

return body;

}

public boolean isValid(){

return valid;

}

} ==================================================共有4个文件，先运行服务段端。。。 这是我以前学的时候写过的！希望能帮的上你

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