[英]How to avoid java.net.BindException: Address already in use
以下是运行1小时然后关闭:
public class Mp extends JWindow implements MouseListener, MouseMotionListener {
public static Mp j;
private int serverPort = 0;
private ServerSocket serverSock = null;
private Socket sock = null;
public static void main(final String[] args) throws IOException, InterruptedException, Exception {
j = new Mp();
j.setVisible(true);
j.waitForConnections();
}
public void waitForConnections() {
while (true) {
try {
sock = serverSock.accept();
System.out.println("[TCPMediaHandler]: Accepted new socket");
TCPMediaHandler handler = new TCPMediaHandler(sock);
handler.start();
} catch (IOException e) {
e.printStackTrace(System.err);
}
}
}
public Mp() throws IOException {
this.serverPort = 38891;
serverSock = new ServerSocket(serverPort);
serverSock.setReuseAddress(true);
//serverSock.setSoTimeout(500);
//serverSock.setSoLinger(true, 0);
System.out.println("[TCPMediaHandler]: Server started");
this.v1.setBackground(Color.BLACK);
this.v1.addMouseListener(this);
/* Close the window */
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
});
}
当我重新运行相同的东西时,它失败并出现java.net.BindException
:
$ java -cp /var/tmp/dist/Mp.jar test.Mp
Exception in thread "main" java.net.BindException: Address already in use
at java.net.PlainSocketImpl.socketBind(Native Method)
at java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:353)
at java.net.ServerSocket.bind(ServerSocket.java:336)
at java.net.ServerSocket.<init>(ServerSocket.java:202)
at java.net.ServerSocket.<init>(ServerSocket.java:114)
at test.Mp.<init>(Mp.java)
at test.Mp.main(Mp.java)
它需要大约3到4分钟才能再次成功执行。 关机后如何立即使用?
跟进:
$ netstat | grep 38891
tcp 35 0 localhost:38891 localhost:37842 CLOSE_WAIT
tcp 0 0 localhost:34955 localhost:38891 ESTABLISHED
tcp 32 0 localhost:38891 localhost:37824 CLOSE_WAIT
tcp 0 0 localhost:38891 localhost:34955 ESTABLISHED
$ lsof -w -n -i tcp:38891
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
xdg-scree 5254 sun 29u IPv4 231948 0t0 TCP *:38891 (LISTEN)
xdg-scree 5355 sun 29u IPv4 231948 0t0 TCP *:38891 (LISTEN)
xdg-scree 5455 sun 29u IPv4 231948 0t0 TCP *:38891 (LISTEN)
telnet 7058 sun 3u IPv4 242987 0t0 TCP 127.0.0.1:34955->127.0.0.1:38891 (ESTABLISHED)
sleep 9002 sun 29u IPv4 231948 0t0 TCP *:38891 (LISTEN)
sleep 9005 sun 29u IPv4 231948 0t0 TCP *:38891 (LISTEN)
sleep 9008 sun 29u IPv4 231948 0t0 TCP *:38891 (LISTEN)
你会看到你的setReuseAddress(true)被调用太晚了,即在bind抛出异常之后。
您可以分三步创建一个未绑定的ServerSocket,使其可重用,然后绑定它。
ServerSocket ss = new ServerSocket();
ss.setReuseAddress(true);
ss.bind(new InetSocketAddress(12345));
我在我的一个程序中遇到了类似的问题,但最终我只是从我的IDE中运行了一个程序实例 - 我没有注意到。 总是仔细检查后台没有运行的东西。
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