出于教育目的，我尝试制作一个服务器和一个客户端，其中服务器从多个客户端接收数据并回显每条消息。问题是，当我尝试让服务器一次将回显发送到所有客户端时。

public class SocketServer {

ArrayList ts = new ArrayList();

ServerSocket serv;

static MainServerThread mst = new MainServerThread();

// ^ IDE(eclipse) underlines this as the problem

SocketServer() {

EventQueue.invokeLater(mst);

}

public static void main(String[] args) {

Thread tr = new Thread(mst);

tr.start();

}

void send(String s) {

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

MyRunnable tmp = ts.get(i);

tmp.sendToClient(s);

}

}

class MainServerThread implements Runnable {

public void run() {

try {

serv = new ServerSocket(13131);

boolean done = false;

while (!done) {

Socket s = serv.accept();

MyRunnable r = new MyRunnable(s);

Thread t = new Thread(r);

ts.add(r);

t.start();

}

} catch(Exception e) {

e.printStackTrace();

}

}

}

class MyRunnable implements Runnable {

Socket sock;

PrintWriter out;

Scanner in;

MyRunnable(Socket soc) {

sock = soc;

}

public void run() {

try {

try {

out = new PrintWriter(sock.getOutputStream(), true);

in = new Scanner(sock.getInputStream());

boolean done = false;

while (!done) {

String line = in.nextLine();

send("Echo: " + line);

System.out.println("Echo: " + line);

if (line.trim().equals("BYE")) done = true;

}

} finally {

sock.close();

}

} catch (Exception e) {

e.printStackTrace();

}

}

public void sendToClient(String s) {

out.println(s);

}

}

}

我搜寻并回答了许多类似的问题，但是没有一个对我有帮助。希望你能指出我的错误。提前致谢。