套接字:使用 Java 发现端口可用性 [英] Sockets: Discover port availability using Java

问题描述

如何使用 Java 以编程方式确定给定机器中端口的可用性?

How do I programmatically determine the availability of a port in a given machine using Java?

即给定一个端口号，确定它是否已经被使用?

i.e given a port number, determine whether it is already being used or not?.

推荐答案

这是实现 来自 Apache camel 项目:

This is the implementation coming from the Apache camel project:

/**
 * Checks to see if a specific port is available.
 *
 * @param port the port to check for availability
 */
public static boolean available(int port) {
    if (port < MIN_PORT_NUMBER || port > MAX_PORT_NUMBER) {
        throw new IllegalArgumentException("Invalid start port: " + port);
    }

    ServerSocket ss = null;
    DatagramSocket ds = null;
    try {
        ss = new ServerSocket(port);
        ss.setReuseAddress(true);
        ds = new DatagramSocket(port);
        ds.setReuseAddress(true);
        return true;
    } catch (IOException e) {
    } finally {
        if (ds != null) {
            ds.close();
        }

        if (ss != null) {
            try {
                ss.close();
            } catch (IOException e) {
                /* should not be thrown */
            }
        }
    }

    return false;
}

他们也在检查 DatagramSocket 以检查端口是否在 UDP 和 TCP 中可用.

They are checking the DatagramSocket as well to check if the port is avaliable in UDP and TCP.

希望这会有所帮助.

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