套接字异常:套接字已关闭

Question

我想创建服务器，这是能够与多个客户端连接。我的主要功能是：

ServerSocket serverSocket = null;
    try {
        serverSocket = new ServerSocket(5556);
    } catch (IOException ex) {
        Logger.getLogger(MakaoServer.class.getName()).log(Level.SEVERE, null, ex);
    }
    while (true) {
        try {
            Socket connection = serverSocket.accept();
            PlayerConnection playerConn = new PlayerConnection(connection);
            playerConn.start();
        } catch (IOException ex) {
            System.out.println("Nie można było utworzyć gniazda.");
        }
    }

PlayerConnection是一个线程类。run方法：

public void run() {
    InputStream input = null;
    while (true) {
        try {
            input = connection.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(input));
            String msg = reader.readLine();
            System.out.println(msg);

        } catch (IOException ex) {
            Logger.getLogger(PlayerConnection.class.getName()).log(Level.SEVERE, null, ex);
        } finally {

        }
    }
}

当我运行客户端并将消息发送到服务器时，它被接收到了，但是在下一次while循环迭代中，connection.getInputStream()；抛出了一个套接字异常，套接字被关闭。为什么？

java.net.SocketException: socket closed
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:150)
at java.net.SocketInputStream.read(SocketInputStream.java:121)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:283)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:325)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:177)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.BufferedReader.fill(BufferedReader.java:154)
at java.io.BufferedReader.readLine(BufferedReader.java:317)
at java.io.BufferedReader.readLine(BufferedReader.java:382)
at makaoserver.PlayerConnection.run(PlayerConnection.java:38)

Answer 1

将输入流和缓冲的读取器放在循环之外。

可能是创建连接到同一个输入流的多个流导致了这种情况。

Answer 2

试一试

public void run() {
    InputStream input = null;
    input = connection.getInputStream();
    BufferedReader reader = new BufferedReader(new InputStreamReader(input));

    while (true) {
        try {
            String msg = reader.readLine();
            System.out.println(msg);
        } catch (IOException ex) {
            Logger.getLogger(PlayerConnection.class.getName()).log(Level.SEVERE, null, ex);
        } finally {

        }
    }
}

使用完套接字后，也不要忘记关闭套接字

try {
  // Create objects
  // do stuff
} finally {
  if (obj != null) obj.close();
}