用java在远程机器上打开ServerSocket？

发布于 2024-12-08 00:10:18 字数 616 浏览 2 评论 0原文

我创建了一个简单的方法来尝试确定远程计算机上的套接字是否打开。这是我的代码：

public static Boolean isPortAvailable( int port, String bindAddr  ) {
    try { 
        System.out.println("IP: " + InetAddress.getByName(bindAddr ));
        ServerSocket srv = new ServerSocket(port, 0, InetAddress.getByName(bindAddr ) );  

        srv.close();  
        srv = null;  
        return true;  

    } catch (IOException e) {  
        return false;  
    }
}

传递这两个参数：

String bindAddr  = "remotemachinename";
int port = 1719;

它继续告诉我端口不可用，但如果我在机器上尝试 netstat -a ，我会发现它显然没有在使用中。我错过了什么吗？

原文

I've created a simple method in attempts to determine if a socket is open on a remote machine. Here is my code:

public static Boolean isPortAvailable( int port, String bindAddr  ) {
    try { 
        System.out.println("IP: " + InetAddress.getByName(bindAddr ));
        ServerSocket srv = new ServerSocket(port, 0, InetAddress.getByName(bindAddr ) );  

        srv.close();  
        srv = null;  
        return true;  

    } catch (IOException e) {  
        return false;  
    }
}

Passing it these two args:

String bindAddr  = "remotemachinename";
int port = 1719;

It continues to tell me the port is not available but if I try netstat -a on the machine I see it's clearly NOT in use. Am I missing something?

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星星的轨迹 2024-12-15 00:10:18

如果您想联系侦听（服务器）套接字，您应该使用 Socket 而不是 ServerSocket。参见ServerSocket javadoc，第三个参数ServerSocket 构造函数是要绑定的本地地址，而不是要连接的远程地址。

试试这个：

try {
    InetAddress addr = InetAddress.getByName(bindAddr);
    Socket sock = new Socket();
    SocketAddress sockaddr = new InetSocketAddress(addr, port);
    int timeout = 1000;   // wait for 1 second = 1000ms (adapt to your use case)
    sock.connect(sockaddr, timeout);
} catch (UnknownHostException e) {
} catch (SocketTimeoutException e) {
    // nobody's listening or willing to accept our connection...
} catch (IOException e) {
}

If you want to contact a listening (server) socket you should use a Socket not a ServerSocket. See the ServerSocket javadoc, the third parameter of the ServerSocket constructor is a local address to bind to, not a remote address to connect to.

Try this:

try {
    InetAddress addr = InetAddress.getByName(bindAddr);
    Socket sock = new Socket();
    SocketAddress sockaddr = new InetSocketAddress(addr, port);
    int timeout = 1000;   // wait for 1 second = 1000ms (adapt to your use case)
    sock.connect(sockaddr, timeout);
} catch (UnknownHostException e) {
} catch (SocketTimeoutException e) {
    // nobody's listening or willing to accept our connection...
} catch (IOException e) {
}

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