直接上代码，这是网上找的demo，然后自己根据需求做了一定的修改。代码可以直接运行
服务器端：
package socket;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;
public class Server extends ServerSocket {
private static final int SERVER_PORT = 7777;
public static boolean isPrint = false;// 是否输出消息标志
private static List user_list = new ArrayList();// 登录用户集合
private static List<ServerThread> thread_list = new ArrayList<ServerThread>();// 服务器已启用线程集合
public static LinkedList<String> message_list = new LinkedList<String>();// 存放消息队列
/**
* 创建服务端Socket,创建向客户端发送消息线程,监听客户端请求并处理
*/
public Server() throws IOException {
super(SERVER_PORT);// 创建ServerSocket
new PrintOutThread();// 创建向客户端发送消息线程
new ListennerSocket();//创建监听客户端连接请求线程
}
/**
* 监听客户端连接请求线程
* @author zhang
* @date 2014-3-28-上午11:21:01
*
*/
class ListennerSocket extends Thread{
public ListennerSocket() {
start();
}
@Override
public void run() {
try {
while (true) {// 监听客户端请求，启个线程处理
Socket socket = accept();
new ServerThread(socket);
}
} catch (Exception e) {
} finally {
try {
close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
* 监听是否有输出消息请求线程类,向客户端发送消息
*/
class PrintOutThread extends Thread {
public PrintOutThread() {
start();
}
@Override
public void run() {
while (true) {
if (isPrint) {// 将缓存在队列中的消息按顺序发送到各客户端，并从队列中清除。
String message = message_list.getFirst();
for (ServerThread thread : thread_list) {
thread.sendMessage(message);
}
message_list.removeFirst();
isPrint = message_list.size() > 0 ? true : false;
}
}
}
}
/**
* 服务器线程类
*/
class ServerThread extends Thread {
private Socket client;
private PrintWriter out;
private BufferedReader in;
private String name;
public ServerThread(Socket s) throws IOException {
client = s;
out = new PrintWriter(client.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(
client.getInputStream()));
// in.readLine();
out.println("成功连上聊天室,请输入你的名字：");
start();
}
@Override
public void run() {
try {
int flag = 0;
String line = in.readLine();
while (!"bye".equals(line)) {
// 查看在线用户列表
if ("showuser".equals(line)) {
out.println(this.listOnlineUsers());
line = in.readLine();
}
// 第一次进入，保存名字
if (flag++ == 0) {
name = line;
user_list.add(name);
thread_list.add(this);
out.println(name + "你好,可以开始聊天了...");
this.pushMessage("Client<" + name + ">进入聊天室...");
} else {
this.pushMessage("Client<" + name + "> say : " + line);
}
line = in.readLine();
}
out.println("byeClient");
} catch (Exception e) {
e.printStackTrace();
} finally {// 用户退出聊天室
try {
client.close();
} catch (IOException e) {
e.printStackTrace();
}
thread_list.remove(this);
user_list.remove(name);
pushMessage("Client<" + name + ">退出了聊天室");
}
}
// 放入消息队列末尾，准备发送给客户端
public void pushMessage(String msg) {
message_list.addLast(msg);
isPrint = true;
}
// 向客户端发送一条消息
private void sendMessage(String msg) {
out.println(msg);
}
// 统计在线用户列表
private String listOnlineUsers() {
String s = "--- 在线用户列表 --- 15 12";
for (int i = 0; i < user_list.size(); i++) {
s += "[" + user_list.get(i) + "] 15 12";
}
s += "--------------------";
return s;
}
}
public static void main(String[] args) throws IOException {
new Server();// 启动服务端
while(true){
Scanner scanner = new Scanner(System.in);
System.out.println("请输入发送给客户端的消息：");
String string = scanner.nextLine();
message_list.addLast(string);
isPrint = true;
}
}
}
客户端：
package socket;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
public class Client extends Socket {
private static final String SERVER_IP = "192.168.21.178";
private static final int SERVER_PORT = 7777;
private Socket client;
private PrintWriter out;
private BufferedReader in;
/**
* 与服务器连接，并输入发送消息
*/
public Client() throws Exception {
super(SERVER_IP, SERVER_PORT);
client = this;
out = new PrintWriter(this.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(this.getInputStream()));
new readLineThread();
while (true) {
in = new BufferedReader(new InputStreamReader(System.in));
String input = in.readLine();
out.println(input);
}
}
/**
* 用于监听服务器端向客户端发送消息线程类
*/
class readLineThread extends Thread {
private BufferedReader buff;
public readLineThread() {
try {
buff = new BufferedReader(new InputStreamReader(
client.getInputStream()));
start();
} catch (Exception e) {
}
}
@Override
public void run() {
try {
while (true) {
String result = buff.readLine();
if ("byeClient".equals(result)) {// 客户端申请退出，服务端返回确认退出
break;
} else {// 输出服务端发送消息
System.out.println(result);
}
}
in.close();
out.close();
client.close();
} catch (Exception e) {
}
}
}
public static void main(String[] args) {
try {
new Client();// 启动客户端
} catch (Exception e) {
}
}
}