Java 服务器没有'；无法使用多个连接

我有一个简单的客户端-服务器应用程序。问题是，它只适用于一个启动的客户机，而不适用于两个或更多的客户机。它可以建立连接，但当您尝试在第一个或第二个字段中输入文本时，服务器会中断。我认为问题可能出在

Server.java

中的函数

broadcast（）

java.lang.IndexOutOfBoundsException: end
     at java.util.regex.Matcher.region(Matcher.java:1038)
     at java.util.Scanner.findPatternInBuffer(Scanner.java:1010)
Client said: sds
    at java.util.Scanner.findWithinHorizon(Scanner.java:1679)
    at java.util.Scanner.nextLine(Scanner.java:1538)
    at Server$NewClient.run(Server.java:66)
    at java.lang.Thread.run(Thread.java:745)

Server.java

public class Server {
    final int PORT = 5000;
    private ArrayList<NewClient> al = new ArrayList<NewClient>();
    private Scanner in;
    private PrintWriter out;
    private SimpleDateFormat sdf;
    private int uniqueID = 0;

    private void go(){

        try{
            ServerSocket serverSocket = new ServerSocket(PORT);
            System.out.println("Waiting for clients...");

            while(true) {
                Socket s = serverSocket.accept();
                NewClient chat = new NewClient(s);
                System.out.println("Client number " + chat.getId() + " connected from: " + s.getLocalAddress().getHostName());
                al.add(chat);
                Thread t = new Thread(chat);
                t.start();

            }
        }catch (Exception e) {
            System.out.println("Problem with establishing network connection: ");
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {
        Server server = new Server();
        server.go();
    }

    class NewClient implements Runnable{
        private Socket socket;
        private int id;

        public NewClient(Socket s) {
            this.socket = s;
            this.id = ++uniqueID;
        }
        public int getId() {
            return this.id;
        }

        @Override
        public void run() {
            try{
                in = new Scanner(socket.getInputStream());
                out = new PrintWriter(socket.getOutputStream());
                sdf = new SimpleDateFormat("HH:mm:ss");

                while(true) {
                    String input = in.nextLine();
                    System.out.println("Client said: " + input);
                    broadcast(input);
                }
            }catch (Exception e) {
                e.printStackTrace();
            }

        }
        private void writeMsg(String input) {
            String msg = input + " on " + sdf.format(new Date());
            out.println("You said: " + msg);
            out.flush();
        }

        private void broadcast(String input) {
            for (int i = 0; i < al.size(); i++) {
                NewClient t = al.get(i);
                t.writeMsg(input);
            }

        }
    }

}

java.lang.IndexOutOfBoundsException: end
     at java.util.regex.Matcher.region(Matcher.java:1038)
     at java.util.Scanner.findPatternInBuffer(Scanner.java:1010)
Client said: sds
    at java.util.Scanner.findWithinHorizon(Scanner.java:1679)
    at java.util.Scanner.nextLine(Scanner.java:1538)
    at Server$NewClient.run(Server.java:66)
    at java.lang.Thread.run(Thread.java:745)

打开两个Client.java并将其连接到server.java时，一切正常。但当我尝试从这两个打开的客户端发送消息时，服务器返回以下错误：

java.lang.IndexOutOfBoundsException: end
     at java.util.regex.Matcher.region(Matcher.java:1038)
     at java.util.Scanner.findPatternInBuffer(Scanner.java:1010)
Client said: sds
    at java.util.Scanner.findWithinHorizon(Scanner.java:1679)
    at java.util.Scanner.nextLine(Scanner.java:1538)
    at Server$NewClient.run(Server.java:66)
    at java.lang.Thread.run(Thread.java:745)

发生的情况是，您的代码扫描来自客户端的第一行（“sds”，它被打印到标准输出），然后它返回并立即尝试扫描来自客户端的下一行。由于客户端还没有发送任何内容，输入流扫描程序会抛出一个异常。
NewClient类是一个内部类。该类的所有实例都是使用外部类的相同实例创建的。更改代码将解决此问题：

java.lang.IndexOutOfBoundsException: end
     at java.util.regex.Matcher.region(Matcher.java:1038)
     at java.util.Scanner.findPatternInBuffer(Scanner.java:1010)
Client said: sds
    at java.util.Scanner.findWithinHorizon(Scanner.java:1679)
    at java.util.Scanner.nextLine(Scanner.java:1538)
    at Server$NewClient.run(Server.java:66)
    at java.lang.Thread.run(Thread.java:745)

public NewClient(Socket s) {
            this.socket = s;
            this.id = ++uniqueID;
            try{
                in = new Scanner(socket.getInputStream());
                out = new PrintWriter(socket.getOutputStream());
                sdf = new SimpleDateFormat("HH:mm:ss");
            }catch(Exception e) {
                System.out.println("Exception while creating input/output streams: " + e);
            }
        }

关于“服务器刹车”的含义，您能给出更多的细节吗？当打开两个Client.java并将其连接到server.java时，一切都正常。但当我试图从这两个打开的客户机发送一些消息时，服务器返回以下错误：java.lang.IndexOutOfBoundsException:end at java.util.regex.Matcher.region（Matcher.java:1038）at java.util.Scanner.FindPatterInBuffer（Scanner.java:1010）客户端说：sds位于java.util.Scanner.findWithinHorizon（Scanner.java:1679）位于java.util.Scanner.nextLine（Scanner.java:1538）位于服务器$NewClient.run（Server.java:66）位于java.lang.Thread.run（Thread.java:745）您丢弃了所有偶数行的客户端输入，而且你永远不会在任何地方检查流的结尾。这不行。我认为问题出在其他地方，因为它发生在节目进入广播消息时，而不广播任何内容。这可能与您的建议有关吗？堆栈跟踪表明错误发生在Scanner.nextLine（）中，从run（）调用时，而不是从broadcast（）方法中调用。broadcast（）中可能还有一个单独的bug，但它不是抛出此堆栈跟踪的bug。