ServerSocket 没有出现在 Netstat 中？

Question

很困惑，我刚刚发布了这个问题但因为我犯了很多错误而将其删除。好吧，这里又来了！我在下面的java中有一个服务器程序。当我运行它时，我希望在 netstat 中看到某种存在，但我什么也没看到。以下是一些屏幕截图：

运行服务器前：https://www.dropbox.com/s/upo9ndbzuxbk9j1/Screenshot%202014-12-24%2002.25.49.png?dl=0

运行服务器后（服务器运行在右上角终端，右下角是客户端，左边显然是netstat）：https://www.dropbox.com/s/05urjvz3lskvzkc/Screenshot%202014-12-24%2002.28.24.png?dl=0

有点长，但这里是服务器（我用 63400 运行它）：

import java.net.*;
import java.io.*;

public class JavaTest2 {
    public static void main(String[] args) throws IOException {

        if (args.length != 1) {
            System.err.println("Usage: java KnockKnockServer <port number>");
            System.exit(1);
        }

        int portNumber = Integer.parseInt(args[0]);

        try (
                ServerSocket serverSocket = new ServerSocket(portNumber);
                Socket clientSocket = serverSocket.accept();
                PrintWriter out =
                        new PrintWriter(clientSocket.getOutputStream(), true);
                BufferedReader in = new BufferedReader(
                        new InputStreamReader(clientSocket.getInputStream()));
        ) {

            String inputLine, outputLine;

            // Initiate conversation with client
            KnockKnockProtocol kkp = new KnockKnockProtocol();
            outputLine = kkp.processInput(null);
            out.println(outputLine);

            while ((inputLine = in.readLine()) != null) {
                outputLine = kkp.processInput(inputLine);
                out.println(outputLine);
                if (outputLine.equals("Bye."))
                    break;
            }
        } catch (IOException e) {
            System.out.println("Exception caught when trying to listen on port "
                    + portNumber + " or listening for a connection");
            System.out.println(e.getMessage());
        }
    }
}

class KnockKnockProtocol {
    private static final int WAITING = 0;
    private static final int SENTKNOCKKNOCK = 1;
    private static final int SENTCLUE = 2;
    private static final int ANOTHER = 3;

    private static final int NUMJOKES = 5;

    private int state = WAITING;
    private int currentJoke = 0;

    private String[] clues = { "Turnip", "Little Old Lady", "Atch", "Who", "Who" };
    private String[] answers = { "Turnip the heat, it's cold in here!",
            "I didn't know you could yodel!",
            "Bless you!",
            "Is there an owl in here?",
            "Is there an echo in here?" };

    public String processInput(String theInput) {
        String theOutput = null;

        if (state == WAITING) {
            theOutput = "Knock! Knock!";
            state = SENTKNOCKKNOCK;
        } else if (state == SENTKNOCKKNOCK) {
            if (theInput.equalsIgnoreCase("Who's there?")) {
                theOutput = clues[currentJoke];
                state = SENTCLUE;
            } else {
                theOutput = "You're supposed to say \"Who's there?\"! " +
                        "Try again. Knock! Knock!";
            }
        } else if (state == SENTCLUE) {
            if (theInput.equalsIgnoreCase(clues[currentJoke] + " who?")) {
                theOutput = answers[currentJoke] + " Want another? (y/n)";
                state = ANOTHER;
            } else {
                theOutput = "You're supposed to say \"" +
                        clues[currentJoke] +
                        " who?\"" +
                        "! Try again. Knock! Knock!";
                state = SENTKNOCKKNOCK;
            }
        } else if (state == ANOTHER) {
            if (theInput.equalsIgnoreCase("y")) {
                theOutput = "Knock! Knock!";
                if (currentJoke == (NUMJOKES - 1))
                    currentJoke = 0;
                else
                    currentJoke++;
                state = SENTKNOCKKNOCK;
            } else {
                theOutput = "Bye.";
                state = WAITING;
            }
        }
        return theOutput;
    }
}

现在，当我运行客户端时，我可以在最顶部看到 netstat 的存在，两个套接字作为我的服务器和客户端在同一台计算机上运行。但仍然没有服务器套接字:(

截图：https://www.dropbox.com/s/bnrbyk41mjob5bg/Screenshot%202014-12-24%2002.25.53.png?dl=0

客户端代码（使用 127.0.0.1 64300 运行）：

import java.io.*;
import java.net.*;

public class JavaTest {
    public static void main(String[] args) throws IOException {

        if (args.length != 2) {
            System.err.println(
                    "Usage: java KnockKnockClient <host name> <port number>");
            System.exit(1);
        }

        String hostName = args[0];
        int portNumber = Integer.parseInt(args[1]);

        try (
                Socket kkSocket = new Socket(hostName, portNumber);
                PrintWriter out = new PrintWriter(kkSocket.getOutputStream(), true);
                BufferedReader in = new BufferedReader(
                        new InputStreamReader(kkSocket.getInputStream()));
        ) {
            BufferedReader stdIn =
                    new BufferedReader(new InputStreamReader(System.in));
            String fromServer;
            String fromUser;

            while ((fromServer = in.readLine()) != null) {
                System.out.println("Server: " + fromServer);
                if (fromServer.equals("Bye."))
                    break;

                fromUser = stdIn.readLine();
                if (fromUser != null) {
                    System.out.println("Client: " + fromUser);
                    out.println(fromUser);
                }
            }
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host " + hostName);
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to " +
                    hostName);
            System.exit(1);
        }
    }
}

提前感谢所有花时间解决问题的人！

我认为它可能只是 netstat 但我仍然想知道为什么当我运行 lsof -i :64300 当只有服务器正在运行时，它显示了我的 java 进程。当我使用我看到的所有内容 3 运行它时（如您在此屏幕截图的左侧终端中看到的 https://www.dropbox.com/s/1focc9dmhkidtan/Screenshot%202014-12-24%2002.52.22.png?dl=0）。在它向我显示我“认为”相关的内容后，我取消了 netstat，因为我无法解释其余部分。我不知道它是否在那里。希望有人帮忙！

好的，我只是在写这篇文章时发现更多，因为我不能发布 90 分钟，但是现在当我使用 intellij idea 并在那里运行它时。只是服务器，没有任何变化，但是当我添加客户端时，我看到了一切！

在任何事情之前：https://www.dropbox.com/s/akupewmprcld0b3/Screenshot%202014-12-24%2002.59.05.png?dl=0

服务器：https://www.dropbox.com/s/uvxmz0jvjozbkyy/Screenshot%202014-12-24%2002.59.34.png?dl=0

客户端+服务器：https://www.dropbox.com/s/bssa16s1n3adwdq/Screenshot%202014-12-24%2003.00.00.png?dl=0

发生了什么事....我还看到 6 个本地主机而不是 3 个...上帝这很有趣，或者我只是犯了一个非常愚蠢的错误。但我开始怀疑这些问题。

Answer 1

netstat 默认忽略监听套接字。所有套接字都有一个 -l 选项或 -all 选项。 – 劳恩