Java 如何在服务器端创建应该给出响应的侦听器？

嗨，我正在用SpringBoot构建项目，并使用socket编程在客户端和服务器之间进行通信。我已经在本地主机上启动了我的项目，端口号为8080。 我使用以下代码运行我的客户端程序：

String serverName = "localhost";
        int port = 8080;
        try {
            System.out.println("Connecting to " + serverName + " on port "
                    + port);
            Socket client = new Socket(serverName, port);
            System.out.println("Just connected to "
                    + client.getRemoteSocketAddress());
            OutputStream outToServer = client.getOutputStream();
            DataOutputStream out = new DataOutputStream(outToServer);
            System.out.println("Hello from " + client.getLocalSocketAddress());
            out.writeUTF("Hello from " + client.getLocalSocketAddress());
            InputStream inFromServer = client.getInputStream();
            DataInputStream in = new DataInputStream(inFromServer);
            System.out.println("Server says " + in.readUTF());
            client.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

此程序打印消息“刚连接到127.0.0.1:8080”，但在“client.close”上方的行引发异常：

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我的要求是如何在服务器端创建侦听器，该侦听器可以处理来自客户端的消息并返回一些响应

我检查了您的代码。连接正常，但当您在.readUTF（）中使用时，客户端不会从服务器响应

您可以使用以下代码：

字符串serverName=“localhost”； int端口=8080

    try {
        System.out.println("Connecting to " + serverName + " on port "
                + port);
        Socket client = new Socket(serverName, port);
        System.out.println("Just connected to "
                + client.getRemoteSocketAddress());
        OutputStream outToServer = client.getOutputStream();
        DataOutputStream out = new DataOutputStream(outToServer);
        System.out.println("Hello from " + client.getLocalSocketAddress());
        out.writeUTF("Hello from " + client.getLocalSocketAddress());
        InputStream inFromServer = client.getInputStream();
        DataInputStream in = new DataInputStream(inFromServer);

        if (in.read() != -1) {
            System.out.println("Server says " + in.readUTF());
        }

        client.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

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因为spring引导在tomcat上运行，而tomcat只理解HTTP。因此，这里您的客户机连接到tomcat服务器，它只能理解HTTP。因此，如果您希望通过HTTP连接到spring boot应用程序，那么请通过TCP连接将HTTP请求发送到spring boot应用程序。否则，在SpringBoot应用程序上实现一个组件，该组件可以在其他端口上接受TCP连接，并根据您的协议进行处理

    try {
        System.out.println("Connecting to " + serverName + " on port "
                + port);
        Socket client = new Socket(serverName, port);
        System.out.println("Just connected to "
                + client.getRemoteSocketAddress());
        OutputStream outToServer = client.getOutputStream();
        DataOutputStream out = new DataOutputStream(outToServer);
        System.out.println("Hello from " + client.getLocalSocketAddress());
        out.writeUTF("Hello from " + client.getLocalSocketAddress());
        InputStream inFromServer = client.getInputStream();
        DataInputStream in = new DataInputStream(inFromServer);

        if (in.read() != -1) {
            System.out.println("Server says " + in.readUTF());
        }

        client.close();
    } catch (IOException e) {
        e.printStackTrace();
    }