简单的C/S聊天室

C/S聊天室分为服务器端和客户端，均需要采用多线程来实现。

服务器端主线程需要不断地监听端口，一旦有客户端的请求时，产生相应的Socket，将其加入到队列中并启动子线程，子线程负责接收客户端消息（使用Socket的getInputStream()函数来处理），再将消息发送到所有的客户端（使用Socket的getOutputStream()函数）。

客户端主线程负责获取键盘输入（相当于侦听键盘输入），并传递给Socket的输出流（使用Socket的getOutputStream()，为什么这里是getOutputStream()，因为对Socket而言是输出流），而子线程负责取得服务器端发过来的消息（使用Socket的getInputStream()）。

代码如下，代码没有实现界面：

import java.io.IOException;import java.net.ServerSocket;import java.net.Socket;import java.util.ArrayList;public class Server {private final int PORT=30000;public static ArrayList<Socket> socketList=new ArrayList<Socket>();public void init(){try (ServerSocket serverSocket=new ServerSocket(PORT);){while(true){Socket socket=serverSocket.accept();socketList.add(socket);new Thread(new ServerThread(socket)).start();}}catch (IOException e) {// TODO Auto-generated catch blockSystem.out.println("服务器启动失败，是否"+PORT+"端口已被占用？");}}public static void main(String[] args) {// TODO Auto-generated method stubServer s=new Server();s.init();}}

import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintStream;import java.net.Socket;public class ServerThread implements Runnable{private Socket s=null;private BufferedReader br=null;public ServerThread(Socket s){this.s=s;}@Overridepublic void run() {// TODO Auto-generated method stubtry {br=new BufferedReader(new InputStreamReader(s.getInputStream()));} catch (IOException e) {// TODO Auto-generated catch blockSystem.out.println("Socket对应的输入流获取失败！");}String content=null;while((content=readFromClient())!=null){for(Socket s:Server.socketList){try (PrintStream ps=new PrintStream(s.getOutputStream()); // 让该程序通过该输出流向socket中输出数据){ps.println(content);}catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}private String readFromClient() {// TODO Auto-generated method stubtry {return br.readLine();} catch (IOException e) {// TODO Auto-generated catch blockServer.socketList.remove(s);}return null;}}

import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintStream;import java.net.Socket;import java.net.UnknownHostException;public class Client {private final static int PORT=30000;private final static String host="127.0.0.1";public static void main(String[] args) throws UnknownHostException, IOException {// TODO Auto-generated method stubSocket s=new Socket(host,PORT);new Thread(new ClientThread(s)).start(); // 子线程完成与服务器通信PrintStream ps=new PrintStream(s.getOutputStream()); // 让程序通过该输出流向Socket中输出数据,得到了socket的输出流String line=null;BufferedReader br=new BufferedReader(new InputStreamReader(System.in));// br.readline()不断读取键盘输入内容while((line=br.readLine())!=null){ps.println(line);}}}

import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.Socket;public class ClientThread implements Runnable {private Socket s=null;private BufferedReader br=null;public ClientThread(Socket s) throws IOException{this.s=s;br=new BufferedReader(new InputStreamReader(s.getInputStream())); // 该句只是返回了这样一个对象，里面并不包含屏幕中的语句}  // 其用readline()的时候才得到输入语句@Overridepublic void run() {// TODO Auto-generated method stubString content=null;try {while((content=br.readLine())!=null) // readline()遇到输入末尾的时候才会返回null{System.out.println(content);}} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}

参考资料：疯狂JAVA讲义